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[VPlan] Set flags when constructing zexts using VPWidenCastRecipe #164198

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Merged
merged 3 commits into from
Oct 20, 2025
Merged

[VPlan] Set flags when constructing zexts using VPWidenCastRecipe #164198

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c6c4969
[VPlan] Set flags when constructing zexts using VPWidenCastRecipe
lukel97 Oct 20, 2025
d15fc60
Add noalias
lukel97 Oct 20, 2025
5e8aa98
Update exit condition
lukel97 Oct 20, 2025
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2 changes: 2 additions & 0 deletions llvm/lib/Transforms/Vectorize/LoopVectorizationPlanner.h
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Original file line number Diff line number Diff line change
Expand Up @@ -325,6 +325,8 @@ class VPBuilder {
VPIRFlags Flags;
if (Opcode == Instruction::Trunc)
Flags = VPIRFlags::TruncFlagsTy(false, false);
else if (Opcode == Instruction::ZExt)
Flags = VPIRFlags::NonNegFlagsTy(false);
return tryInsertInstruction(
new VPWidenCastRecipe(Opcode, Op, ResultTy, Flags));
}
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47 changes: 45 additions & 2 deletions llvm/test/Transforms/LoopVectorize/cse-casts.ll
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Expand Up @@ -319,8 +319,9 @@ define void @preserve_flags_narrowing_extends_and_truncs(ptr noalias %A, ptr noa
; CHECK: [[PRED_STORE_CONTINUE60]]:
; CHECK-NEXT: br label %[[MIDDLE_BLOCK:.*]]
; CHECK: [[MIDDLE_BLOCK]]:
; CHECK-NEXT: br [[EXIT:label %.*]]
; CHECK: [[SCALAR_PH:.*:]]
; CHECK-NEXT: br label %[[EXIT:.*]]
; CHECK: [[EXIT]]:
; CHECK-NEXT: ret void
;
entry:
br label %loop
Expand Down Expand Up @@ -349,3 +350,45 @@ loop:
exit:
ret void
}

define void @simplified_cast_preserves_irflag_type(ptr noalias %p, ptr noalias %q, ptr noalias %r) {
; CHECK-LABEL: define void @simplified_cast_preserves_irflag_type(
; CHECK-SAME: ptr noalias [[P:%.*]], ptr noalias [[Q:%.*]], ptr noalias [[R:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: br label %[[VECTOR_PH:.*]]
; CHECK: [[VECTOR_PH]]:
; CHECK-NEXT: br label %[[VECTOR_BODY:.*]]
; CHECK: [[VECTOR_BODY]]:
; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
; CHECK-NEXT: [[TMP0:%.*]] = load i8, ptr [[P]], align 1
; CHECK-NEXT: [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i8> poison, i8 [[TMP0]], i64 0
; CHECK-NEXT: [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i8> [[BROADCAST_SPLATINSERT]], <4 x i8> poison, <4 x i32> zeroinitializer
; CHECK-NEXT: [[TMP1:%.*]] = zext <4 x i8> [[BROADCAST_SPLAT]] to <4 x i16>
; CHECK-NEXT: [[TMP2:%.*]] = extractelement <4 x i16> [[TMP1]], i32 3
; CHECK-NEXT: store i16 [[TMP2]], ptr [[Q]], align 2
; CHECK-NEXT: store i16 [[TMP2]], ptr [[R]], align 2
; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 8
; CHECK-NEXT: [[TMP3:%.*]] = icmp eq i64 [[INDEX_NEXT]], 48
; CHECK-NEXT: br i1 [[TMP3]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
; CHECK: [[MIDDLE_BLOCK]]:
; CHECK-NEXT: br label %[[SCALAR_PH:.*]]
; CHECK: [[SCALAR_PH]]:
;
entry:
br label %loop

loop:
%iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
%x = load i8, ptr %p
%x.i32 = zext i8 %x to i32
%trunc = trunc i32 %x.i32 to i16
store i16 %trunc, ptr %q
%x.i16 = zext i8 %x to i16
store i16 %x.i16, ptr %r
%iv.next = add i64 %iv, 2
%ec = icmp eq i64 %iv.next, 100
br i1 %ec, label %exit, label %loop

exit:
ret void
}
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