[llvm] [InstSimplify] Fold (a != 0) ? abs(a) : 0 (PR #70305)
Pierre van Houtryve via llvm-commits
llvm-commits at lists.llvm.org
Fri Oct 27 02:44:51 PDT 2023
https://github.com/Pierre-vh updated https://github.com/llvm/llvm-project/pull/70305
>From 1173fdb7b225bf3118de175303cf18c9acdeb183 Mon Sep 17 00:00:00 2001
From: pvanhout <pierre.vanhoutryve at amd.com>
Date: Thu, 26 Oct 2023 10:42:40 +0200
Subject: [PATCH 1/3] [InstCombine] Fold (a != 0) ? abs(a) : 0
Solves #70204
---
.../InstCombine/InstCombineSelect.cpp | 28 +++
.../test/Transforms/InstCombine/select-abs.ll | 193 ++++++++++++++++++
2 files changed, 221 insertions(+)
create mode 100644 llvm/test/Transforms/InstCombine/select-abs.ll
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
index 9bd49f76d4bd5b7..3c44a9bf18e510b 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -1062,6 +1062,31 @@ static Value *foldAbsDiff(ICmpInst *Cmp, Value *TVal, Value *FVal,
return nullptr;
}
+/// Fold
+/// (a == 0) ? 0 : abs(a)
+/// (a != 0) ? abs(a) : 0
+/// into:
+/// abs(a)
+static Value *foldSelectZeroAbs(ICmpInst *Cmp, Value *TVal, Value *FVal,
+ InstCombiner::BuilderTy &Builder) {
+ Value *A = nullptr;
+ CmpInst::Predicate Pred;
+ if (!match(Cmp, m_ICmp(Pred, m_Value(A), m_Zero())))
+ return nullptr;
+
+ if (Pred == CmpInst::ICMP_EQ) {
+ if (match(TVal, m_Zero()) &&
+ match(FVal, m_Intrinsic<Intrinsic::abs>(m_Specific(A))))
+ return FVal;
+ } else if (Pred == CmpInst::ICMP_NE) {
+ if (match(TVal, m_Intrinsic<Intrinsic::abs>(m_Specific(A))) &&
+ match(FVal, m_Zero()))
+ return TVal;
+ }
+
+ return nullptr;
+}
+
/// Fold the following code sequence:
/// \code
/// int a = ctlz(x & -x);
@@ -1809,6 +1834,9 @@ Instruction *InstCombinerImpl::foldSelectInstWithICmp(SelectInst &SI,
if (Value *V = foldAbsDiff(ICI, TrueVal, FalseVal, Builder))
return replaceInstUsesWith(SI, V);
+ if (Value *V = foldSelectZeroAbs(ICI, TrueVal, FalseVal, Builder))
+ return replaceInstUsesWith(SI, V);
+
return Changed ? &SI : nullptr;
}
diff --git a/llvm/test/Transforms/InstCombine/select-abs.ll b/llvm/test/Transforms/InstCombine/select-abs.ll
new file mode 100644
index 000000000000000..2953c0a44eaa1a1
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/select-abs.ll
@@ -0,0 +1,193 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -passes=instcombine < %s | FileCheck %s
+
+declare <4 x i16> @llvm.abs.v4i16(<4 x i16>, i1 immarg)
+declare i32 @llvm.abs.i32(i32, i1 immarg)
+declare i64 @llvm.abs.i64(i64, i1 immarg)
+
+
+define i32 @select_i32_eq0_abs_f(i32 %a) {
+; CHECK-LABEL: @select_i32_eq0_abs_f(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[ABS:%.*]] = tail call i32 @llvm.abs.i32(i32 [[A:%.*]], i1 false)
+; CHECK-NEXT: ret i32 [[ABS]]
+;
+entry:
+ %cond = icmp eq i32 %a, 0
+ %abs = tail call i32 @llvm.abs.i32(i32 %a, i1 false)
+ %res = select i1 %cond, i32 0, i32 %abs
+ ret i32 %res
+}
+
+define i32 @select_i32_eq0_abs_t(i32 %a) {
+; CHECK-LABEL: @select_i32_eq0_abs_t(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[ABS:%.*]] = tail call i32 @llvm.abs.i32(i32 [[A:%.*]], i1 true)
+; CHECK-NEXT: ret i32 [[ABS]]
+;
+entry:
+ %cond = icmp eq i32 %a, 0
+ %abs = tail call i32 @llvm.abs.i32(i32 %a, i1 true)
+ %res = select i1 %cond, i32 0, i32 %abs
+ ret i32 %res
+}
+
+define i32 @select_i32_ne0_abs_f(i32 %a) {
+; CHECK-LABEL: @select_i32_ne0_abs_f(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[ABS:%.*]] = tail call i32 @llvm.abs.i32(i32 [[A:%.*]], i1 false)
+; CHECK-NEXT: ret i32 [[ABS]]
+;
+entry:
+ %cond = icmp ne i32 %a, 0
+ %abs = tail call i32 @llvm.abs.i32(i32 %a, i1 false)
+ %res = select i1 %cond, i32 %abs, i32 0
+ ret i32 %res
+}
+
+define i32 @select_i32_ne0_abs_t(i32 %a) {
+; CHECK-LABEL: @select_i32_ne0_abs_t(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[ABS:%.*]] = tail call i32 @llvm.abs.i32(i32 [[A:%.*]], i1 true)
+; CHECK-NEXT: ret i32 [[ABS]]
+;
+entry:
+ %cond = icmp ne i32 %a, 0
+ %abs = tail call i32 @llvm.abs.i32(i32 %a, i1 true)
+ %res = select i1 %cond, i32 %abs, i32 0
+ ret i32 %res
+}
+
+define i64 @select_i64_eq0_abs_t(i64 %a) {
+; CHECK-LABEL: @select_i64_eq0_abs_t(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[ABS:%.*]] = tail call i64 @llvm.abs.i64(i64 [[A:%.*]], i1 true)
+; CHECK-NEXT: ret i64 [[ABS]]
+;
+entry:
+ %cond = icmp eq i64 %a, 0
+ %abs = tail call i64 @llvm.abs.i64(i64 %a, i1 true)
+ %res = select i1 %cond, i64 0, i64 %abs
+ ret i64 %res
+}
+
+define i64 @select_i64_ne0_abs_t(i64 %a) {
+; CHECK-LABEL: @select_i64_ne0_abs_t(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[ABS:%.*]] = tail call i64 @llvm.abs.i64(i64 [[A:%.*]], i1 true)
+; CHECK-NEXT: ret i64 [[ABS]]
+;
+entry:
+ %cond = icmp ne i64 %a, 0
+ %abs = tail call i64 @llvm.abs.i64(i64 %a, i1 true)
+ %res = select i1 %cond, i64 %abs, i64 0
+ ret i64 %res
+}
+
+define <4 x i16> @select_v4i16_eq0_abs_t(<4 x i16> %a) {
+; CHECK-LABEL: @select_v4i16_eq0_abs_t(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[ABS:%.*]] = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> [[A:%.*]], i1 true)
+; CHECK-NEXT: ret <4 x i16> [[ABS]]
+;
+entry:
+ %cond = icmp eq <4 x i16> %a, <i16 0, i16 0, i16 0, i16 0>
+ %abs = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> %a, i1 true)
+ %res = select <4 x i1> %cond, <4 x i16> <i16 0, i16 0, i16 0, i16 0>, <4 x i16> %abs
+ ret <4 x i16> %res
+}
+
+define <4 x i16> @select_v4i16_ne0_abs_t(<4 x i16> %a) {
+; CHECK-LABEL: @select_v4i16_ne0_abs_t(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[ABS:%.*]] = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> [[A:%.*]], i1 true)
+; CHECK-NEXT: ret <4 x i16> [[ABS]]
+;
+entry:
+ %cond = icmp ne <4 x i16> %a, <i16 0, i16 0, i16 0, i16 0>
+ %abs = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> %a, i1 true)
+ %res = select <4 x i1> %cond, <4 x i16> %abs, <4 x i16> <i16 0, i16 0, i16 0, i16 0>
+ ret <4 x i16> %res
+}
+
+define <4 x i16> @select_v4i16_ne0_abs_t_with_undef(<4 x i16> %a) {
+; CHECK-LABEL: @select_v4i16_ne0_abs_t_with_undef(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[ABS:%.*]] = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> [[A:%.*]], i1 true)
+; CHECK-NEXT: ret <4 x i16> [[ABS]]
+;
+entry:
+ %cond = icmp ne <4 x i16> %a, <i16 0, i16 0, i16 0, i16 0>
+ %abs = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> %a, i1 true)
+ %res = select <4 x i1> %cond, <4 x i16> %abs, <4 x i16> <i16 undef, i16 0, i16 0, i16 0>
+ ret <4 x i16> %res
+}
+
+define i32 @bad_select_i32_ne0_abs(i32 %a) {
+; CHECK-LABEL: @bad_select_i32_ne0_abs(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: ret i32 0
+;
+entry:
+ %cond = icmp ne i32 %a, 0
+ %abs = tail call i32 @llvm.abs.i32(i32 %a, i1 false)
+ %res = select i1 %cond, i32 0, i32 %abs
+ ret i32 %res
+}
+
+define i32 @bad_select_i32_eq0_abs(i32 %a) {
+; CHECK-LABEL: @bad_select_i32_eq0_abs(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: ret i32 0
+;
+entry:
+ %cond = icmp eq i32 %a, 0
+ %abs = tail call i32 @llvm.abs.i32(i32 %a, i1 false)
+ %res = select i1 %cond, i32 %abs, i32 0
+ ret i32 %res
+}
+
+define <4 x i16> @badsplat1_select_v4i16_ne0_abs(<4 x i16> %a) {
+; CHECK-LABEL: @badsplat1_select_v4i16_ne0_abs(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[COND_NOT:%.*]] = icmp eq <4 x i16> [[A:%.*]], <i16 0, i16 1, i16 0, i16 0>
+; CHECK-NEXT: [[ABS:%.*]] = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> [[A]], i1 true)
+; CHECK-NEXT: [[RES:%.*]] = select <4 x i1> [[COND_NOT]], <4 x i16> <i16 0, i16 1, i16 0, i16 0>, <4 x i16> [[ABS]]
+; CHECK-NEXT: ret <4 x i16> [[RES]]
+;
+entry:
+ %cond = icmp ne <4 x i16> %a, <i16 0, i16 1, i16 0, i16 0>
+ %abs = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> %a, i1 true)
+ %res = select <4 x i1> %cond, <4 x i16> %abs, <4 x i16> <i16 0, i16 1, i16 0, i16 0>
+ ret <4 x i16> %res
+}
+
+define <4 x i16> @badsplat2_select_v4i16_ne0_abs(<4 x i16> %a) {
+; CHECK-LABEL: @badsplat2_select_v4i16_ne0_abs(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[COND_NOT:%.*]] = icmp eq <4 x i16> [[A:%.*]], <i16 0, i16 undef, i16 0, i16 0>
+; CHECK-NEXT: [[ABS:%.*]] = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> [[A]], i1 true)
+; CHECK-NEXT: [[RES:%.*]] = select <4 x i1> [[COND_NOT]], <4 x i16> <i16 0, i16 1, i16 0, i16 0>, <4 x i16> [[ABS]]
+; CHECK-NEXT: ret <4 x i16> [[RES]]
+;
+entry:
+ %cond = icmp ne <4 x i16> %a, <i16 0, i16 undef, i16 0, i16 0>
+ %abs = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> %a, i1 true)
+ %res = select <4 x i1> %cond, <4 x i16> %abs, <4 x i16> <i16 0, i16 1, i16 0, i16 0>
+ ret <4 x i16> %res
+}
+
+define <4 x i16> @badsplat3_select_v4i16_ne0_abs(<4 x i16> %a) {
+; CHECK-LABEL: @badsplat3_select_v4i16_ne0_abs(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[COND_NOT:%.*]] = icmp eq <4 x i16> [[A:%.*]], zeroinitializer
+; CHECK-NEXT: [[ABS:%.*]] = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> [[A]], i1 true)
+; CHECK-NEXT: [[RES:%.*]] = select <4 x i1> [[COND_NOT]], <4 x i16> <i16 0, i16 1, i16 0, i16 0>, <4 x i16> [[ABS]]
+; CHECK-NEXT: ret <4 x i16> [[RES]]
+;
+entry:
+ %cond = icmp ne <4 x i16> %a, <i16 0, i16 0, i16 0, i16 0>
+ %abs = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> %a, i1 true)
+ %res = select <4 x i1> %cond, <4 x i16> %abs, <4 x i16> <i16 0, i16 1, i16 0, i16 0>
+ ret <4 x i16> %res
+}
>From 67b68052142e8d263cb8bd0b0ac092c9adf506a8 Mon Sep 17 00:00:00 2001
From: pvanhout <pierre.vanhoutryve at amd.com>
Date: Thu, 26 Oct 2023 13:06:34 +0200
Subject: [PATCH 2/3] Change to instsimplify
---
llvm/lib/Analysis/InstructionSimplify.cpp | 11 ++++++--
.../InstCombine/InstCombineSelect.cpp | 28 -------------------
.../test/Transforms/InstCombine/select-abs.ll | 19 +++++++++----
3 files changed, 22 insertions(+), 36 deletions(-)
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index b3feb2470e58efd..2e2965f07546638 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -4443,8 +4443,15 @@ static Value *simplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp,
// TODO: This may be unsound, because it only catches some forms of
// refinement.
if (!AllowRefinement) {
- if (canCreatePoison(cast<Operator>(I), !DropFlags))
- return nullptr;
+ if (canCreatePoison(cast<Operator>(I), !DropFlags)) {
+ // abs cannot create poison if the value is known to never be int_min.
+ if (auto *II = dyn_cast<IntrinsicInst>(I);
+ II && II->getIntrinsicID() == Intrinsic::abs) {
+ if (!ConstOps[0]->isNotMinSignedValue())
+ return nullptr;
+ } else
+ return nullptr;
+ }
Constant *Res = ConstantFoldInstOperands(I, ConstOps, Q.DL, Q.TLI);
if (DropFlags && Res && I->hasPoisonGeneratingFlagsOrMetadata())
DropFlags->push_back(I);
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
index 3c44a9bf18e510b..9bd49f76d4bd5b7 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -1062,31 +1062,6 @@ static Value *foldAbsDiff(ICmpInst *Cmp, Value *TVal, Value *FVal,
return nullptr;
}
-/// Fold
-/// (a == 0) ? 0 : abs(a)
-/// (a != 0) ? abs(a) : 0
-/// into:
-/// abs(a)
-static Value *foldSelectZeroAbs(ICmpInst *Cmp, Value *TVal, Value *FVal,
- InstCombiner::BuilderTy &Builder) {
- Value *A = nullptr;
- CmpInst::Predicate Pred;
- if (!match(Cmp, m_ICmp(Pred, m_Value(A), m_Zero())))
- return nullptr;
-
- if (Pred == CmpInst::ICMP_EQ) {
- if (match(TVal, m_Zero()) &&
- match(FVal, m_Intrinsic<Intrinsic::abs>(m_Specific(A))))
- return FVal;
- } else if (Pred == CmpInst::ICMP_NE) {
- if (match(TVal, m_Intrinsic<Intrinsic::abs>(m_Specific(A))) &&
- match(FVal, m_Zero()))
- return TVal;
- }
-
- return nullptr;
-}
-
/// Fold the following code sequence:
/// \code
/// int a = ctlz(x & -x);
@@ -1834,9 +1809,6 @@ Instruction *InstCombinerImpl::foldSelectInstWithICmp(SelectInst &SI,
if (Value *V = foldAbsDiff(ICI, TrueVal, FalseVal, Builder))
return replaceInstUsesWith(SI, V);
- if (Value *V = foldSelectZeroAbs(ICI, TrueVal, FalseVal, Builder))
- return replaceInstUsesWith(SI, V);
-
return Changed ? &SI : nullptr;
}
diff --git a/llvm/test/Transforms/InstCombine/select-abs.ll b/llvm/test/Transforms/InstCombine/select-abs.ll
index 2953c0a44eaa1a1..38ee40fa7b42bcb 100644
--- a/llvm/test/Transforms/InstCombine/select-abs.ll
+++ b/llvm/test/Transforms/InstCombine/select-abs.ll
@@ -84,11 +84,14 @@ entry:
ret i64 %res
}
+; TODO: Handle vector cases?
define <4 x i16> @select_v4i16_eq0_abs_t(<4 x i16> %a) {
; CHECK-LABEL: @select_v4i16_eq0_abs_t(
; CHECK-NEXT: entry:
-; CHECK-NEXT: [[ABS:%.*]] = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> [[A:%.*]], i1 true)
-; CHECK-NEXT: ret <4 x i16> [[ABS]]
+; CHECK-NEXT: [[COND:%.*]] = icmp eq <4 x i16> [[A:%.*]], zeroinitializer
+; CHECK-NEXT: [[ABS:%.*]] = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> [[A]], i1 true)
+; CHECK-NEXT: [[RES:%.*]] = select <4 x i1> [[COND]], <4 x i16> zeroinitializer, <4 x i16> [[ABS]]
+; CHECK-NEXT: ret <4 x i16> [[RES]]
;
entry:
%cond = icmp eq <4 x i16> %a, <i16 0, i16 0, i16 0, i16 0>
@@ -100,8 +103,10 @@ entry:
define <4 x i16> @select_v4i16_ne0_abs_t(<4 x i16> %a) {
; CHECK-LABEL: @select_v4i16_ne0_abs_t(
; CHECK-NEXT: entry:
-; CHECK-NEXT: [[ABS:%.*]] = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> [[A:%.*]], i1 true)
-; CHECK-NEXT: ret <4 x i16> [[ABS]]
+; CHECK-NEXT: [[COND_NOT:%.*]] = icmp eq <4 x i16> [[A:%.*]], zeroinitializer
+; CHECK-NEXT: [[ABS:%.*]] = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> [[A]], i1 true)
+; CHECK-NEXT: [[RES:%.*]] = select <4 x i1> [[COND_NOT]], <4 x i16> zeroinitializer, <4 x i16> [[ABS]]
+; CHECK-NEXT: ret <4 x i16> [[RES]]
;
entry:
%cond = icmp ne <4 x i16> %a, <i16 0, i16 0, i16 0, i16 0>
@@ -113,8 +118,10 @@ entry:
define <4 x i16> @select_v4i16_ne0_abs_t_with_undef(<4 x i16> %a) {
; CHECK-LABEL: @select_v4i16_ne0_abs_t_with_undef(
; CHECK-NEXT: entry:
-; CHECK-NEXT: [[ABS:%.*]] = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> [[A:%.*]], i1 true)
-; CHECK-NEXT: ret <4 x i16> [[ABS]]
+; CHECK-NEXT: [[COND_NOT:%.*]] = icmp eq <4 x i16> [[A:%.*]], zeroinitializer
+; CHECK-NEXT: [[ABS:%.*]] = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> [[A]], i1 true)
+; CHECK-NEXT: [[RES:%.*]] = select <4 x i1> [[COND_NOT]], <4 x i16> <i16 undef, i16 0, i16 0, i16 0>, <4 x i16> [[ABS]]
+; CHECK-NEXT: ret <4 x i16> [[RES]]
;
entry:
%cond = icmp ne <4 x i16> %a, <i16 0, i16 0, i16 0, i16 0>
>From bea6bb4be5e4abd786f487c23c3cd4196ab7f8ff Mon Sep 17 00:00:00 2001
From: pvanhout <pierre.vanhoutryve at amd.com>
Date: Fri, 27 Oct 2023 11:44:38 +0200
Subject: [PATCH 3/3] Move test + add more testcases
---
.../select-abs.ll | 170 ++++++++++++++++--
1 file changed, 159 insertions(+), 11 deletions(-)
rename llvm/test/Transforms/{InstCombine => InstSimplify}/select-abs.ll (51%)
diff --git a/llvm/test/Transforms/InstCombine/select-abs.ll b/llvm/test/Transforms/InstSimplify/select-abs.ll
similarity index 51%
rename from llvm/test/Transforms/InstCombine/select-abs.ll
rename to llvm/test/Transforms/InstSimplify/select-abs.ll
index 38ee40fa7b42bcb..6b4708443fb2618 100644
--- a/llvm/test/Transforms/InstCombine/select-abs.ll
+++ b/llvm/test/Transforms/InstSimplify/select-abs.ll
@@ -1,10 +1,11 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -S -passes=instcombine < %s | FileCheck %s
+; RUN: opt -S -passes=instsimplify < %s | FileCheck %s
declare <4 x i16> @llvm.abs.v4i16(<4 x i16>, i1 immarg)
declare i32 @llvm.abs.i32(i32, i1 immarg)
declare i64 @llvm.abs.i64(i64, i1 immarg)
+; check (a == 0) ? 0 : abs(a)
define i32 @select_i32_eq0_abs_f(i32 %a) {
; CHECK-LABEL: @select_i32_eq0_abs_f(
@@ -32,6 +33,153 @@ entry:
ret i32 %res
}
+; check (a == int_min) ? int_min : abs(a)
+
+define i32 @select_i32_eqINTMIN_abs_f(i32 %a) {
+; CHECK-LABEL: @select_i32_eqINTMIN_abs_f(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[ABS:%.*]] = tail call i32 @llvm.abs.i32(i32 [[A:%.*]], i1 false)
+; CHECK-NEXT: ret i32 [[ABS]]
+;
+entry:
+ %cond = icmp eq i32 %a, -2147483648
+ %abs = tail call i32 @llvm.abs.i32(i32 %a, i1 false)
+ %res = select i1 %cond, i32 -2147483648, i32 %abs
+ ret i32 %res
+}
+
+; should not transform
+define i32 @select_i32_eqINTMIN_abs_t(i32 %a) {
+; CHECK-LABEL: @select_i32_eqINTMIN_abs_t(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[COND:%.*]] = icmp eq i32 [[A:%.*]], -2147483648
+; CHECK-NEXT: [[ABS:%.*]] = tail call i32 @llvm.abs.i32(i32 [[A]], i1 true)
+; CHECK-NEXT: [[RES:%.*]] = select i1 [[COND]], i32 -2147483648, i32 [[ABS]]
+; CHECK-NEXT: ret i32 [[RES]]
+;
+entry:
+ %cond = icmp eq i32 %a, -2147483648
+ %abs = tail call i32 @llvm.abs.i32(i32 %a, i1 true)
+ %res = select i1 %cond, i32 -2147483648, i32 %abs
+ ret i32 %res
+}
+
+; check random values, like (a == -255) ? 255 : abs(a)
+define i32 @select_i32_eqneg255_abs_f(i32 %a) {
+; CHECK-LABEL: @select_i32_eqneg255_abs_f(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[ABS:%.*]] = tail call i32 @llvm.abs.i32(i32 [[A:%.*]], i1 false)
+; CHECK-NEXT: ret i32 [[ABS]]
+;
+entry:
+ %cond = icmp eq i32 %a, -255
+ %abs = tail call i32 @llvm.abs.i32(i32 %a, i1 false)
+ %res = select i1 %cond, i32 255, i32 %abs
+ ret i32 %res
+}
+
+define i32 @select_i32_eqneg255_abs_t(i32 %a) {
+; CHECK-LABEL: @select_i32_eqneg255_abs_t(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[ABS:%.*]] = tail call i32 @llvm.abs.i32(i32 [[A:%.*]], i1 true)
+; CHECK-NEXT: ret i32 [[ABS]]
+;
+entry:
+ %cond = icmp eq i32 %a, -255
+ %abs = tail call i32 @llvm.abs.i32(i32 %a, i1 true)
+ %res = select i1 %cond, i32 255, i32 %abs
+ ret i32 %res
+}
+
+define i32 @select_i32_eq65555_abs_f(i32 %a) {
+; CHECK-LABEL: @select_i32_eq65555_abs_f(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[ABS:%.*]] = tail call i32 @llvm.abs.i32(i32 [[A:%.*]], i1 false)
+; CHECK-NEXT: ret i32 [[ABS]]
+;
+entry:
+ %cond = icmp eq i32 %a, 65555
+ %abs = tail call i32 @llvm.abs.i32(i32 %a, i1 false)
+ %res = select i1 %cond, i32 65555, i32 %abs
+ ret i32 %res
+}
+
+define i32 @select_i32_eq65555_abs_t(i32 %a) {
+; CHECK-LABEL: @select_i32_eq65555_abs_t(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[ABS:%.*]] = tail call i32 @llvm.abs.i32(i32 [[A:%.*]], i1 true)
+; CHECK-NEXT: ret i32 [[ABS]]
+;
+entry:
+ %cond = icmp eq i32 %a, 65555
+ %abs = tail call i32 @llvm.abs.i32(i32 %a, i1 true)
+ %res = select i1 %cond, i32 65555, i32 %abs
+ ret i32 %res
+}
+
+
+; check random values, but the transform doesn't make sense, e.g.
+; (a == 255) ? -255 : abs(a)
+define i32 @bad_select_i32_eq255_abs_f(i32 %a) {
+; CHECK-LABEL: @bad_select_i32_eq255_abs_f(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[COND:%.*]] = icmp eq i32 [[A:%.*]], 255
+; CHECK-NEXT: [[ABS:%.*]] = tail call i32 @llvm.abs.i32(i32 [[A]], i1 false)
+; CHECK-NEXT: [[RES:%.*]] = select i1 [[COND]], i32 -255, i32 [[ABS]]
+; CHECK-NEXT: ret i32 [[RES]]
+;
+entry:
+ %cond = icmp eq i32 %a, 255
+ %abs = tail call i32 @llvm.abs.i32(i32 %a, i1 false)
+ %res = select i1 %cond, i32 -255, i32 %abs
+ ret i32 %res
+}
+
+define i32 @bad_select_i32_eq255_abs_t(i32 %a) {
+; CHECK-LABEL: @bad_select_i32_eq255_abs_t(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[COND:%.*]] = icmp eq i32 [[A:%.*]], 255
+; CHECK-NEXT: [[ABS:%.*]] = tail call i32 @llvm.abs.i32(i32 [[A]], i1 true)
+; CHECK-NEXT: [[RES:%.*]] = select i1 [[COND]], i32 -255, i32 [[ABS]]
+; CHECK-NEXT: ret i32 [[RES]]
+;
+entry:
+ %cond = icmp eq i32 %a, 255
+ %abs = tail call i32 @llvm.abs.i32(i32 %a, i1 true)
+ %res = select i1 %cond, i32 -255, i32 %abs
+ ret i32 %res
+}
+
+define i32 @bad_select_i32_eq65555_abs_f(i32 %a) {
+; CHECK-LABEL: @bad_select_i32_eq65555_abs_f(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[COND:%.*]] = icmp eq i32 [[A:%.*]], -65555
+; CHECK-NEXT: [[ABS:%.*]] = tail call i32 @llvm.abs.i32(i32 [[A]], i1 false)
+; CHECK-NEXT: [[RES:%.*]] = select i1 [[COND]], i32 65554, i32 [[ABS]]
+; CHECK-NEXT: ret i32 [[RES]]
+;
+entry:
+ %cond = icmp eq i32 %a, -65555
+ %abs = tail call i32 @llvm.abs.i32(i32 %a, i1 false)
+ %res = select i1 %cond, i32 65554, i32 %abs
+ ret i32 %res
+}
+
+define i32 @bad_select_i32_eq65555_abs_t(i32 %a) {
+; CHECK-LABEL: @bad_select_i32_eq65555_abs_t(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[COND:%.*]] = icmp eq i32 [[A:%.*]], -65555
+; CHECK-NEXT: [[ABS:%.*]] = tail call i32 @llvm.abs.i32(i32 [[A]], i1 true)
+; CHECK-NEXT: [[RES:%.*]] = select i1 [[COND]], i32 65554, i32 [[ABS]]
+; CHECK-NEXT: ret i32 [[RES]]
+;
+entry:
+ %cond = icmp eq i32 %a, -65555
+ %abs = tail call i32 @llvm.abs.i32(i32 %a, i1 true)
+ %res = select i1 %cond, i32 65554, i32 %abs
+ ret i32 %res
+}
+
define i32 @select_i32_ne0_abs_f(i32 %a) {
; CHECK-LABEL: @select_i32_ne0_abs_f(
; CHECK-NEXT: entry:
@@ -103,9 +251,9 @@ entry:
define <4 x i16> @select_v4i16_ne0_abs_t(<4 x i16> %a) {
; CHECK-LABEL: @select_v4i16_ne0_abs_t(
; CHECK-NEXT: entry:
-; CHECK-NEXT: [[COND_NOT:%.*]] = icmp eq <4 x i16> [[A:%.*]], zeroinitializer
+; CHECK-NEXT: [[COND:%.*]] = icmp ne <4 x i16> [[A:%.*]], zeroinitializer
; CHECK-NEXT: [[ABS:%.*]] = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> [[A]], i1 true)
-; CHECK-NEXT: [[RES:%.*]] = select <4 x i1> [[COND_NOT]], <4 x i16> zeroinitializer, <4 x i16> [[ABS]]
+; CHECK-NEXT: [[RES:%.*]] = select <4 x i1> [[COND]], <4 x i16> [[ABS]], <4 x i16> zeroinitializer
; CHECK-NEXT: ret <4 x i16> [[RES]]
;
entry:
@@ -118,9 +266,9 @@ entry:
define <4 x i16> @select_v4i16_ne0_abs_t_with_undef(<4 x i16> %a) {
; CHECK-LABEL: @select_v4i16_ne0_abs_t_with_undef(
; CHECK-NEXT: entry:
-; CHECK-NEXT: [[COND_NOT:%.*]] = icmp eq <4 x i16> [[A:%.*]], zeroinitializer
+; CHECK-NEXT: [[COND:%.*]] = icmp ne <4 x i16> [[A:%.*]], zeroinitializer
; CHECK-NEXT: [[ABS:%.*]] = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> [[A]], i1 true)
-; CHECK-NEXT: [[RES:%.*]] = select <4 x i1> [[COND_NOT]], <4 x i16> <i16 undef, i16 0, i16 0, i16 0>, <4 x i16> [[ABS]]
+; CHECK-NEXT: [[RES:%.*]] = select <4 x i1> [[COND]], <4 x i16> [[ABS]], <4 x i16> <i16 undef, i16 0, i16 0, i16 0>
; CHECK-NEXT: ret <4 x i16> [[RES]]
;
entry:
@@ -157,9 +305,9 @@ entry:
define <4 x i16> @badsplat1_select_v4i16_ne0_abs(<4 x i16> %a) {
; CHECK-LABEL: @badsplat1_select_v4i16_ne0_abs(
; CHECK-NEXT: entry:
-; CHECK-NEXT: [[COND_NOT:%.*]] = icmp eq <4 x i16> [[A:%.*]], <i16 0, i16 1, i16 0, i16 0>
+; CHECK-NEXT: [[COND:%.*]] = icmp ne <4 x i16> [[A:%.*]], <i16 0, i16 1, i16 0, i16 0>
; CHECK-NEXT: [[ABS:%.*]] = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> [[A]], i1 true)
-; CHECK-NEXT: [[RES:%.*]] = select <4 x i1> [[COND_NOT]], <4 x i16> <i16 0, i16 1, i16 0, i16 0>, <4 x i16> [[ABS]]
+; CHECK-NEXT: [[RES:%.*]] = select <4 x i1> [[COND]], <4 x i16> [[ABS]], <4 x i16> <i16 0, i16 1, i16 0, i16 0>
; CHECK-NEXT: ret <4 x i16> [[RES]]
;
entry:
@@ -172,9 +320,9 @@ entry:
define <4 x i16> @badsplat2_select_v4i16_ne0_abs(<4 x i16> %a) {
; CHECK-LABEL: @badsplat2_select_v4i16_ne0_abs(
; CHECK-NEXT: entry:
-; CHECK-NEXT: [[COND_NOT:%.*]] = icmp eq <4 x i16> [[A:%.*]], <i16 0, i16 undef, i16 0, i16 0>
+; CHECK-NEXT: [[COND:%.*]] = icmp ne <4 x i16> [[A:%.*]], <i16 0, i16 undef, i16 0, i16 0>
; CHECK-NEXT: [[ABS:%.*]] = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> [[A]], i1 true)
-; CHECK-NEXT: [[RES:%.*]] = select <4 x i1> [[COND_NOT]], <4 x i16> <i16 0, i16 1, i16 0, i16 0>, <4 x i16> [[ABS]]
+; CHECK-NEXT: [[RES:%.*]] = select <4 x i1> [[COND]], <4 x i16> [[ABS]], <4 x i16> <i16 0, i16 1, i16 0, i16 0>
; CHECK-NEXT: ret <4 x i16> [[RES]]
;
entry:
@@ -187,9 +335,9 @@ entry:
define <4 x i16> @badsplat3_select_v4i16_ne0_abs(<4 x i16> %a) {
; CHECK-LABEL: @badsplat3_select_v4i16_ne0_abs(
; CHECK-NEXT: entry:
-; CHECK-NEXT: [[COND_NOT:%.*]] = icmp eq <4 x i16> [[A:%.*]], zeroinitializer
+; CHECK-NEXT: [[COND:%.*]] = icmp ne <4 x i16> [[A:%.*]], zeroinitializer
; CHECK-NEXT: [[ABS:%.*]] = tail call <4 x i16> @llvm.abs.v4i16(<4 x i16> [[A]], i1 true)
-; CHECK-NEXT: [[RES:%.*]] = select <4 x i1> [[COND_NOT]], <4 x i16> <i16 0, i16 1, i16 0, i16 0>, <4 x i16> [[ABS]]
+; CHECK-NEXT: [[RES:%.*]] = select <4 x i1> [[COND]], <4 x i16> [[ABS]], <4 x i16> <i16 0, i16 1, i16 0, i16 0>
; CHECK-NEXT: ret <4 x i16> [[RES]]
;
entry:
More information about the llvm-commits
mailing list