[DAG] SelectionDAG::canCreateUndefOrPoison - AVGFLOOR/AVGCEIL don't create undef/poison #157056
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@llvm/pr-subscribers-backend-x86 @llvm/pr-subscribers-llvm-selectiondag Author: Simon Pilgrim (RKSimon) ChangesAVGFLOORU: https://alive2.llvm.org/ce/z/4pfi4i The signed variants are still proving annoying to get test cases to work properly Fixes half of #147696 Full diff: https://github.com/llvm/llvm-project/pull/157056.diff 2 Files Affected:
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 9668d253d52ae..63a9f8bc2c615 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -5670,6 +5670,8 @@ bool SelectionDAG::canCreateUndefOrPoison(SDValue Op, const APInt &DemandedElts,
case ISD::UADDSAT:
case ISD::SSUBSAT:
case ISD::USUBSAT:
+ case ISD::AVGFLOORU:
+ case ISD::AVGCEILU:
case ISD::MULHU:
case ISD::MULHS:
case ISD::ABDU:
diff --git a/llvm/test/CodeGen/AArch64/freeze.ll b/llvm/test/CodeGen/AArch64/freeze.ll
index 2a33a4c061dce..7a9d6b7e52457 100644
--- a/llvm/test/CodeGen/AArch64/freeze.ll
+++ b/llvm/test/CodeGen/AArch64/freeze.ll
@@ -430,16 +430,13 @@ define <8 x i16> @freeze_abds(<8 x i16> %a, <8 x i16> %b) {
ret <8 x i16> %r
}
-; TODO: Unnecessary final and
define <8 x i16> @freeze_uhadd(<8 x i16> %a0, <8 x i16> %a1) {
; CHECK-LABEL: freeze_uhadd:
; CHECK: // %bb.0:
; CHECK-NEXT: movi v2.8h, #15
; CHECK-NEXT: and v0.16b, v0.16b, v2.16b
; CHECK-NEXT: and v1.16b, v1.16b, v2.16b
-; CHECK-NEXT: movi v2.8h, #31
; CHECK-NEXT: uhadd v0.8h, v0.8h, v1.8h
-; CHECK-NEXT: and v0.16b, v0.16b, v2.16b
; CHECK-NEXT: ret
%m0 = and <8 x i16> %a0, splat (i16 15)
%m1 = and <8 x i16> %a1, splat (i16 15)
@@ -449,16 +446,13 @@ define <8 x i16> @freeze_uhadd(<8 x i16> %a0, <8 x i16> %a1) {
ret <8 x i16> %masked
}
-; TODO: Unnecessary final and
define <8 x i16> @freeze_urhadd(<8 x i16> %a0, <8 x i16> %a1) {
; CHECK-LABEL: freeze_urhadd:
; CHECK: // %bb.0:
; CHECK-NEXT: movi v2.8h, #15
; CHECK-NEXT: and v0.16b, v0.16b, v2.16b
; CHECK-NEXT: and v1.16b, v1.16b, v2.16b
-; CHECK-NEXT: movi v2.8h, #31
; CHECK-NEXT: urhadd v0.8h, v0.8h, v1.8h
-; CHECK-NEXT: and v0.16b, v0.16b, v2.16b
; CHECK-NEXT: ret
%m0 = and <8 x i16> %a0, splat (i16 15)
%m1 = and <8 x i16> %a1, splat (i16 15)
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@llvm/pr-subscribers-backend-aarch64 Author: Simon Pilgrim (RKSimon) ChangesAVGFLOORU: https://alive2.llvm.org/ce/z/4pfi4i The signed variants are still proving annoying to get test cases to work properly Fixes half of #147696 Full diff: https://github.com/llvm/llvm-project/pull/157056.diff 2 Files Affected:
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 9668d253d52ae..63a9f8bc2c615 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -5670,6 +5670,8 @@ bool SelectionDAG::canCreateUndefOrPoison(SDValue Op, const APInt &DemandedElts,
case ISD::UADDSAT:
case ISD::SSUBSAT:
case ISD::USUBSAT:
+ case ISD::AVGFLOORU:
+ case ISD::AVGCEILU:
case ISD::MULHU:
case ISD::MULHS:
case ISD::ABDU:
diff --git a/llvm/test/CodeGen/AArch64/freeze.ll b/llvm/test/CodeGen/AArch64/freeze.ll
index 2a33a4c061dce..7a9d6b7e52457 100644
--- a/llvm/test/CodeGen/AArch64/freeze.ll
+++ b/llvm/test/CodeGen/AArch64/freeze.ll
@@ -430,16 +430,13 @@ define <8 x i16> @freeze_abds(<8 x i16> %a, <8 x i16> %b) {
ret <8 x i16> %r
}
-; TODO: Unnecessary final and
define <8 x i16> @freeze_uhadd(<8 x i16> %a0, <8 x i16> %a1) {
; CHECK-LABEL: freeze_uhadd:
; CHECK: // %bb.0:
; CHECK-NEXT: movi v2.8h, #15
; CHECK-NEXT: and v0.16b, v0.16b, v2.16b
; CHECK-NEXT: and v1.16b, v1.16b, v2.16b
-; CHECK-NEXT: movi v2.8h, #31
; CHECK-NEXT: uhadd v0.8h, v0.8h, v1.8h
-; CHECK-NEXT: and v0.16b, v0.16b, v2.16b
; CHECK-NEXT: ret
%m0 = and <8 x i16> %a0, splat (i16 15)
%m1 = and <8 x i16> %a1, splat (i16 15)
@@ -449,16 +446,13 @@ define <8 x i16> @freeze_uhadd(<8 x i16> %a0, <8 x i16> %a1) {
ret <8 x i16> %masked
}
-; TODO: Unnecessary final and
define <8 x i16> @freeze_urhadd(<8 x i16> %a0, <8 x i16> %a1) {
; CHECK-LABEL: freeze_urhadd:
; CHECK: // %bb.0:
; CHECK-NEXT: movi v2.8h, #15
; CHECK-NEXT: and v0.16b, v0.16b, v2.16b
; CHECK-NEXT: and v1.16b, v1.16b, v2.16b
-; CHECK-NEXT: movi v2.8h, #31
; CHECK-NEXT: urhadd v0.8h, v0.8h, v1.8h
-; CHECK-NEXT: and v0.16b, v0.16b, v2.16b
; CHECK-NEXT: ret
%m0 = and <8 x i16> %a0, splat (i16 15)
%m1 = and <8 x i16> %a1, splat (i16 15)
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2 tasks
… create undef/poison AVGFLOORU: https://alive2.llvm.org/ce/z/4pfi4i AVGCEILU: https://alive2.llvm.org/ce/z/CGvWiA The signed variants are still proving annoying to get test cases to work properly Fixes half of llvm#147696
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jayfoad
approved these changes
Sep 5, 2025
Are you happy if I add AVGFLOORS/AVGCEILS handling top this patch as well? |
Yes. |
RKSimon
changed the title
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AVGFLOORS: https://alive2.llvm.org/ce/z/6TdoQ_
AVGFLOORU: https://alive2.llvm.org/ce/z/4pfi4i
AVGCEILS: https://alive2.llvm.org/ce/z/nWu8WM
AVGCEILU: https://alive2.llvm.org/ce/z/CGvWiA
Fixes #147696