[LV][NFC] Remove undef from function return values #163578

david-arm · 2025-10-15T15:43:28Z

Split off from PR #163525, this standalone patch replaces ret * undef returns with ret void in order to reduce the likelihood of contributors hitting the undef deprecator warning in github.

Split off from PR llvm#163525, this standalone patch replaces `ret * undef` returns with `ret void` in order to reduce the likelihood of contributors hitting the `undef deprecator` warning in github.

llvmbot · 2025-10-15T15:44:08Z

@llvm/pr-subscribers-llvm-transforms

Author: David Sherwood (david-arm)

Changes

Split off from PR #163525, this standalone patch replaces ret * undef returns with ret void in order to reduce the likelihood of contributors hitting the undef deprecator warning in github.

Patch is 26.34 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/163578.diff

15 Files Affected:

(modified) llvm/test/Transforms/LoopVectorize/12-12-11-if-conv.ll (+3-3)
(modified) llvm/test/Transforms/LoopVectorize/ARM/scalar-block-cost.ll (+2-2)
(modified) llvm/test/Transforms/LoopVectorize/X86/avx1.ll (+6-6)
(modified) llvm/test/Transforms/LoopVectorize/X86/conversion-cost.ll (+11-11)
(modified) llvm/test/Transforms/LoopVectorize/X86/runtime-limit.ll (+4-4)
(modified) llvm/test/Transforms/LoopVectorize/X86/unroll-pm.ll (+2-2)
(modified) llvm/test/Transforms/LoopVectorize/bsd_regex.ll (+3-3)
(modified) llvm/test/Transforms/LoopVectorize/if-conversion-nest.ll (+6-6)
(modified) llvm/test/Transforms/LoopVectorize/if-conversion.ll (+6-4)
(modified) llvm/test/Transforms/LoopVectorize/invariant-store-vectorization.ll (+6-6)
(modified) llvm/test/Transforms/LoopVectorize/memdep.ll (+2-2)
(modified) llvm/test/Transforms/LoopVectorize/partial-lcssa.ll (+2-2)
(modified) llvm/test/Transforms/LoopVectorize/pr28541.ll (+2-2)
(modified) llvm/test/Transforms/LoopVectorize/runtime-check.ll (+8-8)
(modified) llvm/test/Transforms/LoopVectorize/write-only.ll (+6-6)

diff --git a/llvm/test/Transforms/LoopVectorize/12-12-11-if-conv.ll b/llvm/test/Transforms/LoopVectorize/12-12-11-if-conv.ll
index 279d4e82ccb85..83623fd82bb4a 100644
--- a/llvm/test/Transforms/LoopVectorize/12-12-11-if-conv.ll
+++ b/llvm/test/Transforms/LoopVectorize/12-12-11-if-conv.ll
@@ -5,8 +5,8 @@ target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f3
 ;CHECK-LABEL: @foo(
 ;CHECK: icmp eq <4 x i32>
 ;CHECK: select <4 x i1>
-;CHECK: ret i32
-define i32 @foo(i32 %x, i32 %t, ptr nocapture %A) nounwind uwtable ssp {
+;CHECK: ret void
+define void @foo(i32 %x, i32 %t, ptr nocapture %A) nounwind uwtable ssp {
 entry:
   %cmp10 = icmp sgt i32 %x, 0
   br i1 %cmp10, label %for.body, label %for.end
@@ -35,5 +35,5 @@ if.end:                                           ; preds = %for.body, %if.then
   br i1 %exitcond, label %for.end, label %for.body
 
 for.end:                                          ; preds = %if.end, %entry
-  ret i32 undef
+  ret void
 }
diff --git a/llvm/test/Transforms/LoopVectorize/ARM/scalar-block-cost.ll b/llvm/test/Transforms/LoopVectorize/ARM/scalar-block-cost.ll
index 596e42e9f094d..d0c11946c9deb 100644
--- a/llvm/test/Transforms/LoopVectorize/ARM/scalar-block-cost.ll
+++ b/llvm/test/Transforms/LoopVectorize/ARM/scalar-block-cost.ll
@@ -36,7 +36,7 @@ for.body:                                         ; preds = %entry, %for.body
   br i1 %exitcond.not, label %exit, label %for.body
 }
 
-define i32 @if_convert(ptr %a, ptr %b, i32 %start, i32 %end) #0 {
+define void @if_convert(ptr %a, ptr %b, i32 %start, i32 %end) #0 {
 
 ; CHECK-COST-2: LV: Found an estimated cost of 0 for VF 1 For instruction:   %i.032 = phi i32 [ %inc, %if.end ], [ %start, %for.body.preheader ]
 ; CHECK-COST-2-NEXT: LV: Found an estimated cost of 0 for VF 1 For instruction:   %arrayidx = getelementptr inbounds i32, ptr %a, i32 %i.032
@@ -70,7 +70,7 @@ for.cond.cleanup.loopexit:                        ; preds = %if.end
   br label %for.cond.cleanup
 
 for.cond.cleanup:                                 ; preds = %for.cond.cleanup.loopexit, %entry
-  ret i32 undef
+  ret void
 
 for.body:                                         ; preds = %for.body.preheader, %if.end
   %i.032 = phi i32 [ %inc, %if.end ], [ %start, %for.body.preheader ]
diff --git a/llvm/test/Transforms/LoopVectorize/X86/avx1.ll b/llvm/test/Transforms/LoopVectorize/X86/avx1.ll
index 9e205863b8367..44fb8cb2f3beb 100644
--- a/llvm/test/Transforms/LoopVectorize/X86/avx1.ll
+++ b/llvm/test/Transforms/LoopVectorize/X86/avx1.ll
@@ -6,8 +6,8 @@ target triple = "x86_64-apple-macosx10.8.0"
 
 ; CHECK-LABEL: @read_mod_write_single_ptr(
 ; CHECK: load <8 x float>
-; CHECK: ret i32
-define i32 @read_mod_write_single_ptr(ptr nocapture %a, i32 %n) nounwind uwtable ssp {
+; CHECK: ret void
+define void @read_mod_write_single_ptr(ptr nocapture %a, i32 %n) nounwind uwtable ssp {
   %1 = icmp sgt i32 %n, 0
   br i1 %1, label %.lr.ph, label %._crit_edge
 
@@ -23,15 +23,15 @@ define i32 @read_mod_write_single_ptr(ptr nocapture %a, i32 %n) nounwind uwtable
   br i1 %exitcond, label %._crit_edge, label %.lr.ph
 
 ._crit_edge:                                      ; preds = %.lr.ph, %0
-  ret i32 undef
+  ret void
 }
 
 
 ; CHECK-LABEL: @read_mod_i64(
 ; SLOWMEM32: load <2 x i64>
 ; FASTMEM32: load <4 x i64>
-; CHECK: ret i32
-define i32 @read_mod_i64(ptr nocapture %a, i32 %n) nounwind uwtable ssp {
+; CHECK: ret void
+define void @read_mod_i64(ptr nocapture %a, i32 %n) nounwind uwtable ssp {
   %1 = icmp sgt i32 %n, 0
   br i1 %1, label %.lr.ph, label %._crit_edge
 
@@ -47,6 +47,6 @@ define i32 @read_mod_i64(ptr nocapture %a, i32 %n) nounwind uwtable ssp {
   br i1 %exitcond, label %._crit_edge, label %.lr.ph
 
 ._crit_edge:                                      ; preds = %.lr.ph, %0
-  ret i32 undef
+  ret void
 }
 
diff --git a/llvm/test/Transforms/LoopVectorize/X86/conversion-cost.ll b/llvm/test/Transforms/LoopVectorize/X86/conversion-cost.ll
index 6d2cda48f90ca..0287645d9d7f9 100644
--- a/llvm/test/Transforms/LoopVectorize/X86/conversion-cost.ll
+++ b/llvm/test/Transforms/LoopVectorize/X86/conversion-cost.ll
@@ -4,7 +4,7 @@
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx10.8.0"
 
-define i32 @conversion_cost1(i32 %n, ptr nocapture %A, ptr nocapture %B) nounwind uwtable ssp {
+define void @conversion_cost1(i32 %n, ptr nocapture %A, ptr nocapture %B) nounwind uwtable ssp {
 ; CHECK-LABEL: @conversion_cost1(
 ; CHECK-NEXT:    [[TMP1:%.*]] = icmp sgt i32 [[N:%.*]], 3
 ; CHECK-NEXT:    br i1 [[TMP1]], label [[ITER_CHECK:%.*]], label [[DOT_CRIT_EDGE:%.*]]
@@ -37,7 +37,7 @@ define i32 @conversion_cost1(i32 %n, ptr nocapture %A, ptr nocapture %B) nounwin
 ; CHECK:       vec.epilog.iter.check:
 ; CHECK-NEXT:    [[IND_END5:%.*]] = add i64 3, [[N_VEC]]
 ; CHECK-NEXT:    [[MIN_EPILOG_ITERS_CHECK:%.*]] = icmp ult i64 [[N_MOD_VF]], 4
-; CHECK-NEXT:    br i1 [[MIN_EPILOG_ITERS_CHECK]], label [[VEC_EPILOG_SCALAR_PH]], label [[VEC_EPILOG_PH]]
+; CHECK-NEXT:    br i1 [[MIN_EPILOG_ITERS_CHECK]], label [[VEC_EPILOG_SCALAR_PH]], label [[VEC_EPILOG_PH]], !prof [[PROF3:![0-9]+]]
 ; CHECK:       vec.epilog.ph:
 ; CHECK-NEXT:    [[VEC_EPILOG_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[VEC_EPILOG_ITER_CHECK]] ], [ 0, [[VECTOR_MAIN_LOOP_ITER_CHECK]] ]
 ; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[IND_END]], [[VEC_EPILOG_ITER_CHECK]] ], [ 3, [[VECTOR_MAIN_LOOP_ITER_CHECK]] ]
@@ -58,7 +58,7 @@ define i32 @conversion_cost1(i32 %n, ptr nocapture %A, ptr nocapture %B) nounwin
 ; CHECK-NEXT:    [[INDEX_NEXT11]] = add nuw i64 [[INDEX7]], 4
 ; CHECK-NEXT:    [[VEC_IND_NEXT9]] = add <4 x i8> [[VEC_IND8]], splat (i8 4)
 ; CHECK-NEXT:    [[TMP12:%.*]] = icmp eq i64 [[INDEX_NEXT11]], [[N_VEC3]]
-; CHECK-NEXT:    br i1 [[TMP12]], label [[VEC_EPILOG_MIDDLE_BLOCK:%.*]], label [[VEC_EPILOG_VECTOR_BODY]], !llvm.loop [[LOOP3:![0-9]+]]
+; CHECK-NEXT:    br i1 [[TMP12]], label [[VEC_EPILOG_MIDDLE_BLOCK:%.*]], label [[VEC_EPILOG_VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
 ; CHECK:       vec.epilog.middle.block:
 ; CHECK-NEXT:    [[CMP_N12:%.*]] = icmp eq i64 [[TMP3]], [[N_VEC3]]
 ; CHECK-NEXT:    br i1 [[CMP_N12]], label [[DOT_CRIT_EDGE_LOOPEXIT]], label [[VEC_EPILOG_SCALAR_PH]]
@@ -73,11 +73,11 @@ define i32 @conversion_cost1(i32 %n, ptr nocapture %A, ptr nocapture %B) nounwin
 ; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add i64 [[INDVARS_IV]], 1
 ; CHECK-NEXT:    [[LFTR_WIDEIV:%.*]] = trunc i64 [[INDVARS_IV_NEXT]] to i32
 ; CHECK-NEXT:    [[EXITCOND:%.*]] = icmp eq i32 [[LFTR_WIDEIV]], [[N]]
-; CHECK-NEXT:    br i1 [[EXITCOND]], label [[DOT_CRIT_EDGE_LOOPEXIT]], label [[DOTLR_PH]], !llvm.loop [[LOOP4:![0-9]+]]
+; CHECK-NEXT:    br i1 [[EXITCOND]], label [[DOT_CRIT_EDGE_LOOPEXIT]], label [[DOTLR_PH]], !llvm.loop [[LOOP5:![0-9]+]]
 ; CHECK:       ._crit_edge.loopexit:
 ; CHECK-NEXT:    br label [[DOT_CRIT_EDGE]]
 ; CHECK:       ._crit_edge:
-; CHECK-NEXT:    ret i32 undef
+; CHECK-NEXT:    ret void
 ;
   %1 = icmp sgt i32 %n, 3
   br i1 %1, label %.lr.ph, label %._crit_edge
@@ -93,10 +93,10 @@ define i32 @conversion_cost1(i32 %n, ptr nocapture %A, ptr nocapture %B) nounwin
   br i1 %exitcond, label %._crit_edge, label %.lr.ph
 
 ._crit_edge:                                      ; preds = %.lr.ph, %0
-  ret i32 undef
+  ret void
 }
 
-define i32 @conversion_cost2(i32 %n, ptr nocapture %A, ptr nocapture %B) nounwind uwtable ssp {
+define void @conversion_cost2(i32 %n, ptr nocapture %A, ptr nocapture %B) nounwind uwtable ssp {
 ; CHECK-LABEL: @conversion_cost2(
 ; CHECK-NEXT:    [[TMP1:%.*]] = icmp sgt i32 [[N:%.*]], 9
 ; CHECK-NEXT:    br i1 [[TMP1]], label [[DOTLR_PH_PREHEADER:%.*]], label [[DOT_CRIT_EDGE:%.*]]
@@ -136,7 +136,7 @@ define i32 @conversion_cost2(i32 %n, ptr nocapture %A, ptr nocapture %B) nounwin
 ; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 8
 ; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <2 x i64> [[STEP_ADD_3]], splat (i64 2)
 ; CHECK-NEXT:    [[TMP24:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; CHECK-NEXT:    br i1 [[TMP24]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
+; CHECK-NEXT:    br i1 [[TMP24]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
 ; CHECK:       middle.block:
 ; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[TMP3]], [[N_VEC]]
 ; CHECK-NEXT:    br i1 [[CMP_N]], label [[DOT_CRIT_EDGE_LOOPEXIT:%.*]], label [[SCALAR_PH]]
@@ -152,11 +152,11 @@ define i32 @conversion_cost2(i32 %n, ptr nocapture %A, ptr nocapture %B) nounwin
 ; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add i64 [[INDVARS_IV]], 1
 ; CHECK-NEXT:    [[LFTR_WIDEIV:%.*]] = trunc i64 [[INDVARS_IV_NEXT]] to i32
 ; CHECK-NEXT:    [[EXITCOND:%.*]] = icmp eq i32 [[LFTR_WIDEIV]], [[N]]
-; CHECK-NEXT:    br i1 [[EXITCOND]], label [[DOT_CRIT_EDGE_LOOPEXIT]], label [[DOTLR_PH]], !llvm.loop [[LOOP6:![0-9]+]]
+; CHECK-NEXT:    br i1 [[EXITCOND]], label [[DOT_CRIT_EDGE_LOOPEXIT]], label [[DOTLR_PH]], !llvm.loop [[LOOP7:![0-9]+]]
 ; CHECK:       ._crit_edge.loopexit:
 ; CHECK-NEXT:    br label [[DOT_CRIT_EDGE]]
 ; CHECK:       ._crit_edge:
-; CHECK-NEXT:    ret i32 undef
+; CHECK-NEXT:    ret void
 ;
   %1 = icmp sgt i32 %n, 9
   br i1 %1, label %.lr.ph, label %._crit_edge
@@ -173,5 +173,5 @@ define i32 @conversion_cost2(i32 %n, ptr nocapture %A, ptr nocapture %B) nounwin
   br i1 %exitcond, label %._crit_edge, label %.lr.ph
 
 ._crit_edge:                                      ; preds = %.lr.ph, %0
-  ret i32 undef
+  ret void
 }
diff --git a/llvm/test/Transforms/LoopVectorize/X86/runtime-limit.ll b/llvm/test/Transforms/LoopVectorize/X86/runtime-limit.ll
index af5c921c29149..fa3b4a6609d4c 100644
--- a/llvm/test/Transforms/LoopVectorize/X86/runtime-limit.ll
+++ b/llvm/test/Transforms/LoopVectorize/X86/runtime-limit.ll
@@ -13,7 +13,7 @@ target triple = "x86_64-unknown-linux"
 ;CHECK-LABEL: func1x6(
 ;CHECK: <4 x i32>
 ;CHECK: ret
-define i32 @func1x6(ptr nocapture %out, ptr nocapture %A, ptr nocapture %B, ptr nocapture %C, ptr nocapture %D, ptr nocapture %E, ptr nocapture %F) {
+define void @func1x6(ptr nocapture %out, ptr nocapture %A, ptr nocapture %B, ptr nocapture %C, ptr nocapture %D, ptr nocapture %E, ptr nocapture %F) {
 entry:
   br label %for.body
 
@@ -40,14 +40,14 @@ for.body:                                         ; preds = %for.body, %entry
   br i1 %exitcond, label %for.end, label %for.body
 
 for.end:                                          ; preds = %for.body
-  ret i32 undef
+  ret void
 }
 
 ; We are vectorizing with 12 runtime checks.
 ;CHECK-LABEL: func2x6(
 ;CHECK: <4 x i32>
 ;CHECK: ret
-define i32 @func2x6(ptr nocapture %out, ptr nocapture %out2, ptr nocapture %A, ptr nocapture %B, ptr nocapture %C, ptr nocapture %D, ptr nocapture %E, ptr nocapture %F) {
+define void @func2x6(ptr nocapture %out, ptr nocapture %out2, ptr nocapture %A, ptr nocapture %B, ptr nocapture %C, ptr nocapture %D, ptr nocapture %E, ptr nocapture %F) {
 entry:
   br label %for.body
 
@@ -85,5 +85,5 @@ for.body:                                         ; preds = %for.body, %entry
   br i1 %exitcond, label %for.end, label %for.body
 
 for.end:                                          ; preds = %for.body
-  ret i32 undef
+  ret void
 }
diff --git a/llvm/test/Transforms/LoopVectorize/X86/unroll-pm.ll b/llvm/test/Transforms/LoopVectorize/X86/unroll-pm.ll
index 8971dfe507240..47355e7d9dafd 100644
--- a/llvm/test/Transforms/LoopVectorize/X86/unroll-pm.ll
+++ b/llvm/test/Transforms/LoopVectorize/X86/unroll-pm.ll
@@ -11,7 +11,7 @@ target triple = "x86_64-apple-macosx10.8.0"
 ;CHECK-NOUNRL: store <4 x i32>
 ;CHECK-NOUNRL-NOT: store <4 x i32>
 ;CHECK-NOUNRL: ret
-define i32 @bar(ptr nocapture %A, i32 %n) nounwind uwtable ssp {
+define void @bar(ptr nocapture %A, i32 %n) nounwind uwtable ssp {
   %1 = icmp sgt i32 %n, 0
   br i1 %1, label %.lr.ph, label %._crit_edge
 
@@ -27,5 +27,5 @@ define i32 @bar(ptr nocapture %A, i32 %n) nounwind uwtable ssp {
   br i1 %exitcond, label %._crit_edge, label %.lr.ph
 
 ._crit_edge:                                      ; preds = %.lr.ph, %0
-  ret i32 undef
+  ret void
 }
diff --git a/llvm/test/Transforms/LoopVectorize/bsd_regex.ll b/llvm/test/Transforms/LoopVectorize/bsd_regex.ll
index f64255f29d335..b7aa958958734 100644
--- a/llvm/test/Transforms/LoopVectorize/bsd_regex.ll
+++ b/llvm/test/Transforms/LoopVectorize/bsd_regex.ll
@@ -8,7 +8,7 @@ target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f3
 ; When scalarizing stores we need to preserve the original order.
 ; Make sure that we are extracting in the correct order (0101, and not 0011).
 
-define i32 @foo(ptr nocapture %A) {
+define void @foo(ptr nocapture %A) {
 ; CHECK-LABEL: @foo(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    br label [[VECTOR_PH:%.*]]
@@ -39,7 +39,7 @@ define i32 @foo(ptr nocapture %A) {
 ; CHECK:       middle.block:
 ; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
 ; CHECK:       for.end:
-; CHECK-NEXT:    ret i32 undef
+; CHECK-NEXT:    ret void
 ;
 entry:
   br label %for.body
@@ -55,7 +55,7 @@ for.body:
   br i1 %exitcond, label %for.end, label %for.body
 
 for.end:
-  ret i32 undef
+  ret void
 }
 
 
diff --git a/llvm/test/Transforms/LoopVectorize/if-conversion-nest.ll b/llvm/test/Transforms/LoopVectorize/if-conversion-nest.ll
index 1588d02eff3db..51255b2e35707 100644
--- a/llvm/test/Transforms/LoopVectorize/if-conversion-nest.ll
+++ b/llvm/test/Transforms/LoopVectorize/if-conversion-nest.ll
@@ -3,7 +3,7 @@
 
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
 
-define i32 @foo(ptr nocapture %A, ptr nocapture %B, i32 %n) {
+define void @foo(ptr nocapture %A, ptr nocapture %B, i32 %n) {
 ; CHECK-LABEL: @foo(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[CMP26:%.*]] = icmp sgt i32 [[N:%.*]], 0
@@ -73,7 +73,7 @@ define i32 @foo(ptr nocapture %A, ptr nocapture %B, i32 %n) {
 ; CHECK:       for.end.loopexit:
 ; CHECK-NEXT:    br label [[FOR_END]]
 ; CHECK:       for.end:
-; CHECK-NEXT:    ret i32 undef
+; CHECK-NEXT:    ret void
 ;
 entry:
   %cmp26 = icmp sgt i32 %n, 0
@@ -106,11 +106,11 @@ if.end14:
   br i1 %exitcond, label %for.end, label %for.body
 
 for.end:
-  ret i32 undef
+  ret void
 }
 
 ; As above but with multiple variables set per block.
-define i32 @multi_variable_if_nest(ptr nocapture %A, ptr nocapture %B, i32 %n) {
+define void @multi_variable_if_nest(ptr nocapture %A, ptr nocapture %B, i32 %n) {
 ; CHECK-LABEL: @multi_variable_if_nest(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[CMP26:%.*]] = icmp sgt i32 [[N:%.*]], 0
@@ -188,7 +188,7 @@ define i32 @multi_variable_if_nest(ptr nocapture %A, ptr nocapture %B, i32 %n) {
 ; CHECK:       for.end.loopexit:
 ; CHECK-NEXT:    br label [[FOR_END]]
 ; CHECK:       for.end:
-; CHECK-NEXT:    ret i32 undef
+; CHECK-NEXT:    ret void
 ;
 entry:
   %cmp26 = icmp sgt i32 %n, 0
@@ -224,5 +224,5 @@ if.end14:
   br i1 %exitcond, label %for.end, label %for.body
 
 for.end:
-  ret i32 undef
+  ret void
 }
diff --git a/llvm/test/Transforms/LoopVectorize/if-conversion.ll b/llvm/test/Transforms/LoopVectorize/if-conversion.ll
index 8a7f4a386fda1..a88a9b1466149 100644
--- a/llvm/test/Transforms/LoopVectorize/if-conversion.ll
+++ b/llvm/test/Transforms/LoopVectorize/if-conversion.ll
@@ -17,8 +17,8 @@ target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f3
 ;  }
 ;}
 
-define i32 @function0(ptr nocapture %a, ptr nocapture %b, i32 %start, i32 %end) nounwind uwtable ssp {
-; CHECK-LABEL: define i32 @function0(
+define void @function0(ptr nocapture %a, ptr nocapture %b, i32 %start, i32 %end) nounwind uwtable ssp {
+; CHECK-LABEL: define void @function0(
 ; CHECK-SAME: ptr captures(none) [[A:%.*]], ptr captures(none) [[B:%.*]], i32 [[START:%.*]], i32 [[END:%.*]]) #[[ATTR0:[0-9]+]] {
 ; CHECK-NEXT:  [[ENTRY:.*:]]
 ; CHECK-NEXT:    [[CMP16:%.*]] = icmp slt i32 [[START]], [[END]]
@@ -94,7 +94,7 @@ define i32 @function0(ptr nocapture %a, ptr nocapture %b, i32 %start, i32 %end)
 ; CHECK:       [[FOR_END_LOOPEXIT]]:
 ; CHECK-NEXT:    br label %[[FOR_END]]
 ; CHECK:       [[FOR_END]]:
-; CHECK-NEXT:    ret i32 undef
+; CHECK-NEXT:    ret void
 ;
 entry:
   %cmp16 = icmp slt i32 %start, %end
@@ -127,7 +127,7 @@ if.end:
   br i1 %cmp, label %for.body, label %for.end
 
 for.end:
-  ret i32 undef
+  ret void
 }
 
 
@@ -237,6 +237,8 @@ for.end:                                          ; preds = %for.inc, %entry
 ; Handle PHI with single incoming value having a full mask.
 ; PR34523
 
+; NOTE: Changing PHI inputs from undef to poison leads to change in
+; behaviour of the test. Left as undef for now.
 define void @PR34523() {
 ; CHECK-LABEL: define void @PR34523() {
 ; CHECK-NEXT:  [[BB1:.*:]]
diff --git a/llvm/test/Transforms/LoopVectorize/invariant-store-vectorization.ll b/llvm/test/Transforms/LoopVectorize/invariant-store-vectorization.ll
index 742ee649db3a2..eea22374ade30 100644
--- a/llvm/test/Transforms/LoopVectorize/invariant-store-vectorization.ll
+++ b/llvm/test/Transforms/LoopVectorize/invariant-store-vectorization.ll
@@ -337,7 +337,7 @@ for.end:                                          ; preds = %for.body
 ;    }
 ;  }
 
-define i32 @multiple_uniform_stores(ptr nocapture %var1, ptr nocapture readonly %var2, i32 %itr) #0 {
+define void @multiple_uniform_stores(ptr nocapture %var1, ptr nocapture readonly %var2, i32 %itr) #0 {
 ; CHECK-LABEL: @multiple_uniform_stores(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[CMP20:%.*]] = icmp eq i32 [[ITR:%.*]], 0
@@ -429,7 +429,7 @@ define i32 @multiple_uniform_stores(ptr nocapture %var1, ptr nocapture readonly
 ; CHECK:       for.end10.loopexit:
 ; CHECK-NEXT:    br label [[FOR_END10]]
 ; CHECK:       for.end10:
-; CHECK-NEXT:    ret i32 undef
+; CHECK-NEXT:    ret void
 ;
 entry:
   %cmp20 = icmp eq i32 %itr, 0
@@ -469,12 +469,12 @@ for.inc8:                                         ; preds = %for.body3, %for.con
   br i1 %exitcond26, label %for.end10, label %for.cond1.preheader
 
 for.end10:                                        ; preds = %for.inc8, %entry
-  ret i32 undef
+  ret void
 }
 
 ; second uniform store to the same address is conditional.
 ; we do not vectorize this.
-define i32 @multiple_uniform_stores_conditional(ptr nocapture %var1, ptr nocapture readonly %var2, i32 %itr) #0 {
+define void @multiple_uniform_stores_conditional(ptr nocapture %var1, ptr nocapture readonly %var2, i32 %itr) #0 {
 ; CHECK-LABEL: @multiple_uniform_stores_conditional(
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[CMP20:%.*]] = icmp eq i32 [[ITR:%.*]], 0
@@ -520,7 +520,7 @@ define i32 @multiple_uniform_stores_conditional(ptr nocapture %var1, ptr nocaptu
 ; CHECK:       for.end10.loopexit:
 ; CHECK-NEXT:    br label [[FOR_END10]]
 ; CHECK:       for.end10:
-; CHECK-NEXT:    ret i32 undef
+; CHECK-NEXT:    ret void
 ;
 entry:
   %cmp20 = icmp eq i32 %itr, 0
@@ -567,7 +567,7 @@ for.inc8:                                         ; preds = %for.body3, %for.con
   br i1 %exitcond26, label %for.end10, label %for.cond1.preheader
 
 for.end10:                                        ; preds = %for.inc8, %entry
-  ret i32 undef
+  ret void
 }
 
 ; cannot vectorize loop with unsafe dependency between uniform load (%i10) and store
diff --git a/llvm/test/Transforms/LoopVectorize/memdep.ll b/llvm/test/Transforms/LoopVectorize/memdep.ll
index b891b4312f18d..d9d9eec9b7d33 100644
--- a/llvm/test/Transforms/LoopVectorize/memdep.ll
+++ b/llvm/test/Transforms/LoopVectorize/memdep.ll
@@ -132,7 +132,7 @@ for.end:
 ; CHECK-LABEL: @f6
 ; CHECK-NOT: <2 x i32>
 
-define i32 @f6(ptr %a, i32 %tmp) {
+define void @f6(ptr %a, i32 %tmp) {
 entry:
   br label %for.body
 
@@ -149,7 +149,7 @@ for.body:
   br i1 %exitcond, label %for.body, label %for.end
 
 for.end:
-  ret i32 undef
+  ret void
 }
 
 ; Don't vectorize true loop carried dependencies that are not a multiple of the
diff --git a/llvm/test/Transforms/LoopVectorize/partial-lcssa.ll b/llvm/test/Transforms/LoopVectorize/partial-lcssa.ll
index d700d484c56bc..f5e480c910c33 100644
--- a/llvm/test/Transforms/LoopVectorize/partial-lcssa.ll
+++ b/llvm/test/Transforms/LoopVectorize/partial-lcssa.ll
@@ -10,7 +10,7 @@
 ; CHECK: store i64 %indvars.outer, ptr %O2, align 4
 
 
-define i64 @foo(ptr nocapture %A, ptr nocapture %B, i64 %n, i64 %m, ptr %O1, ptr ...
[truncated]

github-actions · 2025-10-15T15:45:05Z

⚠️ undef deprecator found issues in your code. ⚠️

You can test this locally with the following command:

git diff -U0 --pickaxe-regex -S '([^a-zA-Z0-9#_-]undef[^a-zA-Z0-9_-]|UndefValue::get)' 'HEAD~1' HEAD llvm/test/Transforms/LoopVectorize/12-12-11-if-conv.ll llvm/test/Transforms/LoopVectorize/ARM/scalar-block-cost.ll llvm/test/Transforms/LoopVectorize/X86/avx1.ll llvm/test/Transforms/LoopVectorize/X86/conversion-cost.ll llvm/test/Transforms/LoopVectorize/X86/runtime-limit.ll llvm/test/Transforms/LoopVectorize/X86/unroll-pm.ll llvm/test/Transforms/LoopVectorize/bsd_regex.ll llvm/test/Transforms/LoopVectorize/if-conversion-nest.ll llvm/test/Transforms/LoopVectorize/if-conversion.ll llvm/test/Transforms/LoopVectorize/invariant-store-vectorization.ll llvm/test/Transforms/LoopVectorize/memdep.ll llvm/test/Transforms/LoopVectorize/partial-lcssa.ll llvm/test/Transforms/LoopVectorize/pr28541.ll llvm/test/Transforms/LoopVectorize/runtime-check.ll llvm/test/Transforms/LoopVectorize/write-only.ll

The following files introduce new uses of undef:

llvm/test/Transforms/LoopVectorize/if-conversion.ll

Undef is now deprecated and should only be used in the rare cases where no replacement is possible. For example, a load of uninitialized memory yields undef. You should use poison values for placeholders instead.

In tests, avoid using undef and having tests that trigger undefined behavior. If you need an operand with some unimportant value, you can add a new argument to the function and use that instead.

For example, this is considered a bad practice:

define void @fn() {
  ...
  br i1 undef, ...
}

Please use the following instead:

define void @fn(i1 %cond) {
  ...
  br i1 %cond, ...
}

Please refer to the Undefined Behavior Manual for more information.

fhahn

LGTM, thanks

llvm-ci · 2025-10-16T08:58:38Z

LLVM Buildbot has detected a new failure on builder mlir-nvidia running on mlir-nvidia while building llvm at step 7 "test-build-check-mlir-build-only-check-mlir".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/138/builds/20496

Here is the relevant piece of the build log for the reference

Step 7 (test-build-check-mlir-build-only-check-mlir) failure: test (failure)
******************** TEST 'MLIR :: Integration/GPU/CUDA/async.mlir' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -gpu-kernel-outlining  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -pass-pipeline='builtin.module(gpu.module(strip-debuginfo,convert-gpu-to-nvvm),nvvm-attach-target)'  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -gpu-async-region -gpu-to-llvm -reconcile-unrealized-casts -gpu-module-to-binary="format=fatbin"  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -async-to-async-runtime -async-runtime-ref-counting  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -convert-async-to-llvm -convert-func-to-llvm -convert-arith-to-llvm -convert-cf-to-llvm -reconcile-unrealized-casts  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-runner    --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_cuda_runtime.so    --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_async_runtime.so    --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_runner_utils.so    --entry-point-result=void -O0  | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/FileCheck /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -gpu-kernel-outlining
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt '-pass-pipeline=builtin.module(gpu.module(strip-debuginfo,convert-gpu-to-nvvm),nvvm-attach-target)'
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -gpu-async-region -gpu-to-llvm -reconcile-unrealized-casts -gpu-module-to-binary=format=fatbin
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -async-to-async-runtime -async-runtime-ref-counting
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-opt -convert-async-to-llvm -convert-func-to-llvm -convert-arith-to-llvm -convert-cf-to-llvm -reconcile-unrealized-casts
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/mlir-runner --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_cuda_runtime.so --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_async_runtime.so --shared-libs=/vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/lib/libmlir_runner_utils.so --entry-point-result=void -O0
# .---command stderr------------
# | 'cuStreamWaitEvent(stream, event, 0)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventDestroy(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuStreamWaitEvent(stream, event, 0)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventDestroy(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuStreamWaitEvent(stream, event, 0)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuStreamWaitEvent(stream, event, 0)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventDestroy(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventDestroy(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventSynchronize(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# | 'cuEventDestroy(event)' failed with 'CUDA_ERROR_CONTEXT_IS_DESTROYED'
# `-----------------------------
# executed command: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.obj/bin/FileCheck /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir
# .---command stderr------------
# | /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir:68:12: error: CHECK: expected string not found in input
# |  // CHECK: [84, 84]
# |            ^
# | <stdin>:1:1: note: scanning from here
# | Unranked Memref base@ = 0x5776b8748ad0 rank = 1 offset = 0 sizes = [2] strides = [1] data = 
# | ^
# | <stdin>:2:1: note: possible intended match here
# | [42, 42]
# | ^
# | 
# | Input file: <stdin>
# | Check file: /vol/worker/mlir-nvidia/mlir-nvidia/llvm.src/mlir/test/Integration/GPU/CUDA/async.mlir
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |             1: Unranked Memref base@ = 0x5776b8748ad0 rank = 1 offset = 0 sizes = [2] strides = [1] data =  
# | check:68'0     X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
# |             2: [42, 42] 
# | check:68'0     ~~~~~~~~~
# | check:68'1     ?         possible intended match
...

[LV][NFC] Remove undef from function return values

cf9ead1

Split off from PR llvm#163525, this standalone patch replaces `ret * undef` returns with `ret void` in order to reduce the likelihood of contributors hitting the `undef deprecator` warning in github.

david-arm requested review from fhahn and kmclaughlin-arm October 15, 2025 15:43

llvmbot added the llvm:transforms label Oct 15, 2025

fhahn approved these changes Oct 16, 2025

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david-arm merged commit c48aa54 into llvm:main Oct 16, 2025
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[LV][NFC] Remove undef from function return values #163578

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[LV][NFC] Remove undef from function return values #163578

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