[llvm] [InstCombine] Remove m_OneUse requirement or max, but not min (PR #81505)
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Sun Mar 3 10:59:59 PST 2024
https://github.com/AtariDreams updated https://github.com/llvm/llvm-project/pull/81505
>From 218aa726c0b0cf29b0dbea1aabcf15d99a512b17 Mon Sep 17 00:00:00 2001
From: Rose <83477269+AtariDreams at users.noreply.github.com>
Date: Sun, 3 Mar 2024 13:36:32 -0500
Subject: [PATCH 1/2] [Transforms] Add pre-commit tests (NFC)
---
llvm/test/Transforms/InstCombine/maximum.ll | 13 +++++++++++++
llvm/test/Transforms/InstCombine/maxnum.ll | 13 +++++++++++++
2 files changed, 26 insertions(+)
diff --git a/llvm/test/Transforms/InstCombine/maximum.ll b/llvm/test/Transforms/InstCombine/maximum.ll
index 82e4c8794c1c84..a4575d4735013e 100644
--- a/llvm/test/Transforms/InstCombine/maximum.ll
+++ b/llvm/test/Transforms/InstCombine/maximum.ll
@@ -444,3 +444,16 @@ define float @negated_op_extra_use(float %x) {
%r = call float @llvm.maximum.f32(float %negx, float %x)
ret float %r
}
+
+define float @negated_op_extra_use_comm(float %x) {
+; CHECK-LABEL: @negated_op_extra_use_comm(
+; CHECK-NEXT: [[NEGX:%.*]] = fneg float [[X:%.*]]
+; CHECK-NEXT: call void @use(float [[NEGX]])
+; CHECK-NEXT: [[R:%.*]] = call float @llvm.maximum.f32(float [[X]], float [[NEGX]])
+; CHECK-NEXT: ret float [[R]]
+;
+ %negx = fneg float %x
+ call void @use(float %negx)
+ %r = call float @llvm.maximum.f32(float %x, float %negx)
+ ret float %r
+}
diff --git a/llvm/test/Transforms/InstCombine/maxnum.ll b/llvm/test/Transforms/InstCombine/maxnum.ll
index e140a5b405ea84..78339f3475de38 100644
--- a/llvm/test/Transforms/InstCombine/maxnum.ll
+++ b/llvm/test/Transforms/InstCombine/maxnum.ll
@@ -466,3 +466,16 @@ define float @negated_op_extra_use(float %x) {
%r = call float @llvm.maxnum.f32(float %negx, float %x)
ret float %r
}
+
+define float @negated_op_extra_use_comm(float %x) {
+; CHECK-LABEL: @negated_op_extra_use_comm(
+; CHECK-NEXT: [[NEGX:%.*]] = fneg float [[X:%.*]]
+; CHECK-NEXT: call void @use(float [[NEGX]])
+; CHECK-NEXT: [[R:%.*]] = call float @llvm.maxnum.f32(float [[X]], float [[NEGX]])
+; CHECK-NEXT: ret float [[R]]
+;
+ %negx = fneg float %x
+ call void @use(float %negx)
+ %r = call float @llvm.maxnum.f32(float %x, float %negx)
+ ret float %r
+}
>From 06c8a90260dbcba4a5d9fde5f9fab76ddae8287d Mon Sep 17 00:00:00 2001
From: Rose <83477269+AtariDreams at users.noreply.github.com>
Date: Mon, 12 Feb 2024 11:25:24 -0500
Subject: [PATCH 2/2] [Transforms] Remove m_OneUse requirement for max, but not
min
If it is ever determined that min doesn't need one-use, then we can remove the one-use requirement entirely.
---
.../Transforms/InstCombine/InstCombineCalls.cpp | 17 ++++++++++++-----
llvm/test/Transforms/InstCombine/maximum.ll | 4 ++--
llvm/test/Transforms/InstCombine/maxnum.ll | 4 ++--
3 files changed, 16 insertions(+), 9 deletions(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 60b8243d6ba669..50c0f9a913f32a 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -2288,11 +2288,18 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
// max X, -X --> fabs X
// min X, -X --> -(fabs X)
- // TODO: Remove one-use limitation? That is obviously better for max.
- // It would be an extra instruction for min (fnabs), but that is
- // still likely better for analysis and codegen.
- if ((match(Arg0, m_OneUse(m_FNeg(m_Value(X)))) && Arg1 == X) ||
- (match(Arg1, m_OneUse(m_FNeg(m_Value(X)))) && Arg0 == X)) {
+ // TODO: Remove one-use limitation? That is obviously better for max,
+ // hence why we don't check for one-use for that. However,
+ // it would be an extra instruction for min (fnabs), but
+ // that is still likely better for analysis and codegen.
+ auto IsMinMaxOrXNegX = [IID, &X](Value *Op0, Value *Op1) {
+ if (match(Op0, m_FNeg(m_Value(X))) && match(Op1, m_Specific(X)))
+ return Op0->hasOneUse() ||
+ (IID != Intrinsic::minimum && IID != Intrinsic::minnum);
+ return false;
+ };
+
+ if (IsMinMaxOrXNegX(Arg0, Arg1) || IsMinMaxOrXNegX(Arg1, Arg0)) {
Value *R = Builder.CreateUnaryIntrinsic(Intrinsic::fabs, X, II);
if (IID == Intrinsic::minimum || IID == Intrinsic::minnum)
R = Builder.CreateFNegFMF(R, II);
diff --git a/llvm/test/Transforms/InstCombine/maximum.ll b/llvm/test/Transforms/InstCombine/maximum.ll
index a4575d4735013e..7455d3b7b924cc 100644
--- a/llvm/test/Transforms/InstCombine/maximum.ll
+++ b/llvm/test/Transforms/InstCombine/maximum.ll
@@ -436,7 +436,7 @@ define float @negated_op_extra_use(float %x) {
; CHECK-LABEL: @negated_op_extra_use(
; CHECK-NEXT: [[NEGX:%.*]] = fneg float [[X:%.*]]
; CHECK-NEXT: call void @use(float [[NEGX]])
-; CHECK-NEXT: [[R:%.*]] = call float @llvm.maximum.f32(float [[NEGX]], float [[X]])
+; CHECK-NEXT: [[R:%.*]] = call float @llvm.fabs.f32(float [[X]])
; CHECK-NEXT: ret float [[R]]
;
%negx = fneg float %x
@@ -449,7 +449,7 @@ define float @negated_op_extra_use_comm(float %x) {
; CHECK-LABEL: @negated_op_extra_use_comm(
; CHECK-NEXT: [[NEGX:%.*]] = fneg float [[X:%.*]]
; CHECK-NEXT: call void @use(float [[NEGX]])
-; CHECK-NEXT: [[R:%.*]] = call float @llvm.maximum.f32(float [[X]], float [[NEGX]])
+; CHECK-NEXT: [[R:%.*]] = call float @llvm.fabs.f32(float [[X]])
; CHECK-NEXT: ret float [[R]]
;
%negx = fneg float %x
diff --git a/llvm/test/Transforms/InstCombine/maxnum.ll b/llvm/test/Transforms/InstCombine/maxnum.ll
index 78339f3475de38..f26a5300febd85 100644
--- a/llvm/test/Transforms/InstCombine/maxnum.ll
+++ b/llvm/test/Transforms/InstCombine/maxnum.ll
@@ -458,7 +458,7 @@ define float @negated_op_extra_use(float %x) {
; CHECK-LABEL: @negated_op_extra_use(
; CHECK-NEXT: [[NEGX:%.*]] = fneg float [[X:%.*]]
; CHECK-NEXT: call void @use(float [[NEGX]])
-; CHECK-NEXT: [[R:%.*]] = call float @llvm.maxnum.f32(float [[NEGX]], float [[X]])
+; CHECK-NEXT: [[R:%.*]] = call float @llvm.fabs.f32(float [[X]])
; CHECK-NEXT: ret float [[R]]
;
%negx = fneg float %x
@@ -471,7 +471,7 @@ define float @negated_op_extra_use_comm(float %x) {
; CHECK-LABEL: @negated_op_extra_use_comm(
; CHECK-NEXT: [[NEGX:%.*]] = fneg float [[X:%.*]]
; CHECK-NEXT: call void @use(float [[NEGX]])
-; CHECK-NEXT: [[R:%.*]] = call float @llvm.maxnum.f32(float [[X]], float [[NEGX]])
+; CHECK-NEXT: [[R:%.*]] = call float @llvm.fabs.f32(float [[X]])
; CHECK-NEXT: ret float [[R]]
;
%negx = fneg float %x
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