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-rw-r--r--llvm/lib/Transforms/InstCombine/InstructionCombining.cpp28
-rw-r--r--llvm/test/Transforms/InstCombine/vec_shuffle.ll38
2 files changed, 33 insertions, 33 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index f87b94dd355..2b9db4baafa 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -1417,21 +1417,21 @@ Instruction *InstCombiner::foldShuffledBinop(BinaryOperator &Inst) {
}
}
if (MayChange) {
- // It's not safe to use a vector with undef elements because the entire
- // instruction can be folded to undef (for example, div/rem divisors).
- // Replace undef lanes with the first non-undef element. Vector demanded
- // elements can change those back to undef values if that is safe.
- Constant *SafeDummyConstant = nullptr;
- for (unsigned i = 0; i < VWidth; ++i) {
- if (!isa<UndefValue>(NewVecC[i])) {
- SafeDummyConstant = NewVecC[i];
- break;
- }
+ // With integer div/rem instructions, it is not safe to use a vector with
+ // undef elements because the entire instruction can be folded to undef.
+ // So replace undef elements with '1' because that can never induce
+ // undefined behavior. All other binop opcodes are always safe to
+ // speculate, and therefore, it is fine to include undef elements for
+ // unused lanes (and using undefs may help optimization).
+ BinaryOperator::BinaryOps Opcode = Inst.getOpcode();
+ if (Opcode == Instruction::UDiv || Opcode == Instruction::URem ||
+ Opcode == Instruction::SDiv || Opcode == Instruction::SRem) {
+ assert(C->getType()->getScalarType()->isIntegerTy() &&
+ "Not expecting FP opcodes/operands/constants here");
+ for (unsigned i = 0; i < VWidth; ++i)
+ if (isa<UndefValue>(NewVecC[i]))
+ NewVecC[i] = ConstantInt::get(NewVecC[i]->getType(), 1);
}
- assert(SafeDummyConstant && "Undef constant vector was not simplified?");
- for (unsigned i = 0; i < VWidth; ++i)
- if (isa<UndefValue>(NewVecC[i]))
- NewVecC[i] = SafeDummyConstant;
// Op(shuffle(V1, Mask), C) -> shuffle(Op(V1, NewC), Mask)
// Op(C, shuffle(V1, Mask)) -> shuffle(Op(NewC, V1), Mask)
diff --git a/llvm/test/Transforms/InstCombine/vec_shuffle.ll b/llvm/test/Transforms/InstCombine/vec_shuffle.ll
index 59345b8a512..7e863fd2813 100644
--- a/llvm/test/Transforms/InstCombine/vec_shuffle.ll
+++ b/llvm/test/Transforms/InstCombine/vec_shuffle.ll
@@ -452,7 +452,7 @@ define <4 x i32> @mul_const_splat(<4 x i32> %v) {
define <4 x i32> @lshr_const_half_splat(<4 x i32> %v) {
; CHECK-LABEL: @lshr_const_half_splat(
-; CHECK-NEXT: [[TMP1:%.*]] = lshr <4 x i32> <i32 8, i32 8, i32 9, i32 8>, [[V:%.*]]
+; CHECK-NEXT: [[TMP1:%.*]] = lshr <4 x i32> <i32 undef, i32 8, i32 9, i32 undef>, [[V:%.*]]
; CHECK-NEXT: [[R:%.*]] = shufflevector <4 x i32> [[TMP1]], <4 x i32> undef, <4 x i32> <i32 1, i32 1, i32 2, i32 2>
; CHECK-NEXT: ret <4 x i32> [[R]]
;
@@ -643,7 +643,7 @@ define <2 x i32> @mul_splat_constant(<2 x i32> %x) {
define <2 x i32> @shl_splat_constant0(<2 x i32> %x) {
; CHECK-LABEL: @shl_splat_constant0(
-; CHECK-NEXT: [[TMP1:%.*]] = shl <2 x i32> <i32 5, i32 5>, [[X:%.*]]
+; CHECK-NEXT: [[TMP1:%.*]] = shl <2 x i32> <i32 5, i32 undef>, [[X:%.*]]
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x i32> [[TMP1]], <2 x i32> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x i32> [[R]]
;
@@ -654,7 +654,7 @@ define <2 x i32> @shl_splat_constant0(<2 x i32> %x) {
define <2 x i32> @shl_splat_constant1(<2 x i32> %x) {
; CHECK-LABEL: @shl_splat_constant1(
-; CHECK-NEXT: [[TMP1:%.*]] = shl <2 x i32> [[X:%.*]], <i32 5, i32 5>
+; CHECK-NEXT: [[TMP1:%.*]] = shl <2 x i32> [[X:%.*]], <i32 5, i32 undef>
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x i32> [[TMP1]], <2 x i32> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x i32> [[R]]
;
@@ -665,7 +665,7 @@ define <2 x i32> @shl_splat_constant1(<2 x i32> %x) {
define <2 x i32> @ashr_splat_constant0(<2 x i32> %x) {
; CHECK-LABEL: @ashr_splat_constant0(
-; CHECK-NEXT: [[TMP1:%.*]] = lshr <2 x i32> <i32 5, i32 5>, [[X:%.*]]
+; CHECK-NEXT: [[TMP1:%.*]] = ashr <2 x i32> <i32 5, i32 undef>, [[X:%.*]]
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x i32> [[TMP1]], <2 x i32> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x i32> [[R]]
;
@@ -676,7 +676,7 @@ define <2 x i32> @ashr_splat_constant0(<2 x i32> %x) {
define <2 x i32> @ashr_splat_constant1(<2 x i32> %x) {
; CHECK-LABEL: @ashr_splat_constant1(
-; CHECK-NEXT: [[TMP1:%.*]] = ashr <2 x i32> [[X:%.*]], <i32 5, i32 5>
+; CHECK-NEXT: [[TMP1:%.*]] = ashr <2 x i32> [[X:%.*]], <i32 5, i32 undef>
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x i32> [[TMP1]], <2 x i32> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x i32> [[R]]
;
@@ -687,7 +687,7 @@ define <2 x i32> @ashr_splat_constant1(<2 x i32> %x) {
define <2 x i32> @lshr_splat_constant0(<2 x i32> %x) {
; CHECK-LABEL: @lshr_splat_constant0(
-; CHECK-NEXT: [[TMP1:%.*]] = lshr <2 x i32> <i32 5, i32 5>, [[X:%.*]]
+; CHECK-NEXT: [[TMP1:%.*]] = lshr <2 x i32> <i32 5, i32 undef>, [[X:%.*]]
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x i32> [[TMP1]], <2 x i32> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x i32> [[R]]
;
@@ -698,7 +698,7 @@ define <2 x i32> @lshr_splat_constant0(<2 x i32> %x) {
define <2 x i32> @lshr_splat_constant1(<2 x i32> %x) {
; CHECK-LABEL: @lshr_splat_constant1(
-; CHECK-NEXT: [[TMP1:%.*]] = lshr <2 x i32> [[X:%.*]], <i32 5, i32 5>
+; CHECK-NEXT: [[TMP1:%.*]] = lshr <2 x i32> [[X:%.*]], <i32 5, i32 undef>
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x i32> [[TMP1]], <2 x i32> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x i32> [[R]]
;
@@ -720,7 +720,7 @@ define <2 x i32> @urem_splat_constant0(<2 x i32> %x) {
define <2 x i32> @urem_splat_constant1(<2 x i32> %x) {
; CHECK-LABEL: @urem_splat_constant1(
-; CHECK-NEXT: [[TMP1:%.*]] = urem <2 x i32> [[X:%.*]], <i32 42, i32 42>
+; CHECK-NEXT: [[TMP1:%.*]] = urem <2 x i32> [[X:%.*]], <i32 42, i32 1>
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x i32> [[TMP1]], <2 x i32> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x i32> [[R]]
;
@@ -742,7 +742,7 @@ define <2 x i32> @srem_splat_constant0(<2 x i32> %x) {
define <2 x i32> @srem_splat_constant1(<2 x i32> %x) {
; CHECK-LABEL: @srem_splat_constant1(
-; CHECK-NEXT: [[TMP1:%.*]] = srem <2 x i32> [[X:%.*]], <i32 42, i32 42>
+; CHECK-NEXT: [[TMP1:%.*]] = srem <2 x i32> [[X:%.*]], <i32 42, i32 1>
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x i32> [[TMP1]], <2 x i32> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x i32> [[R]]
;
@@ -764,7 +764,7 @@ define <2 x i32> @udiv_splat_constant0(<2 x i32> %x) {
define <2 x i32> @udiv_splat_constant1(<2 x i32> %x) {
; CHECK-LABEL: @udiv_splat_constant1(
-; CHECK-NEXT: [[TMP1:%.*]] = udiv <2 x i32> [[X:%.*]], <i32 42, i32 42>
+; CHECK-NEXT: [[TMP1:%.*]] = udiv <2 x i32> [[X:%.*]], <i32 42, i32 1>
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x i32> [[TMP1]], <2 x i32> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x i32> [[R]]
;
@@ -786,7 +786,7 @@ define <2 x i32> @sdiv_splat_constant0(<2 x i32> %x) {
define <2 x i32> @sdiv_splat_constant1(<2 x i32> %x) {
; CHECK-LABEL: @sdiv_splat_constant1(
-; CHECK-NEXT: [[TMP1:%.*]] = sdiv <2 x i32> [[X:%.*]], <i32 42, i32 42>
+; CHECK-NEXT: [[TMP1:%.*]] = sdiv <2 x i32> [[X:%.*]], <i32 42, i32 1>
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x i32> [[TMP1]], <2 x i32> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x i32> [[R]]
;
@@ -830,7 +830,7 @@ define <2 x i32> @xor_splat_constant(<2 x i32> %x) {
define <2 x float> @fadd_splat_constant(<2 x float> %x) {
; CHECK-LABEL: @fadd_splat_constant(
-; CHECK-NEXT: [[TMP1:%.*]] = fadd <2 x float> [[X:%.*]], <float 4.200000e+01, float 4.200000e+01>
+; CHECK-NEXT: [[TMP1:%.*]] = fadd <2 x float> [[X:%.*]], <float 4.200000e+01, float undef>
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x float> [[TMP1]], <2 x float> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x float> [[R]]
;
@@ -841,7 +841,7 @@ define <2 x float> @fadd_splat_constant(<2 x float> %x) {
define <2 x float> @fsub_splat_constant0(<2 x float> %x) {
; CHECK-LABEL: @fsub_splat_constant0(
-; CHECK-NEXT: [[TMP1:%.*]] = fsub <2 x float> <float 4.200000e+01, float 4.200000e+01>, [[X:%.*]]
+; CHECK-NEXT: [[TMP1:%.*]] = fsub <2 x float> <float 4.200000e+01, float undef>, [[X:%.*]]
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x float> [[TMP1]], <2 x float> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x float> [[R]]
;
@@ -852,7 +852,7 @@ define <2 x float> @fsub_splat_constant0(<2 x float> %x) {
define <2 x float> @fsub_splat_constant1(<2 x float> %x) {
; CHECK-LABEL: @fsub_splat_constant1(
-; CHECK-NEXT: [[TMP1:%.*]] = fadd <2 x float> [[X:%.*]], <float -4.200000e+01, float -4.200000e+01>
+; CHECK-NEXT: [[TMP1:%.*]] = fadd <2 x float> [[X:%.*]], <float -4.200000e+01, float 0x7FF8000000000000>
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x float> [[TMP1]], <2 x float> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x float> [[R]]
;
@@ -863,7 +863,7 @@ define <2 x float> @fsub_splat_constant1(<2 x float> %x) {
define <2 x float> @fmul_splat_constant(<2 x float> %x) {
; CHECK-LABEL: @fmul_splat_constant(
-; CHECK-NEXT: [[TMP1:%.*]] = fmul <2 x float> [[X:%.*]], <float 4.200000e+01, float 4.200000e+01>
+; CHECK-NEXT: [[TMP1:%.*]] = fmul <2 x float> [[X:%.*]], <float 4.200000e+01, float undef>
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x float> [[TMP1]], <2 x float> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x float> [[R]]
;
@@ -874,7 +874,7 @@ define <2 x float> @fmul_splat_constant(<2 x float> %x) {
define <2 x float> @fdiv_splat_constant0(<2 x float> %x) {
; CHECK-LABEL: @fdiv_splat_constant0(
-; CHECK-NEXT: [[TMP1:%.*]] = fdiv <2 x float> <float 4.200000e+01, float 4.200000e+01>, [[X:%.*]]
+; CHECK-NEXT: [[TMP1:%.*]] = fdiv <2 x float> <float 4.200000e+01, float undef>, [[X:%.*]]
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x float> [[TMP1]], <2 x float> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x float> [[R]]
;
@@ -885,7 +885,7 @@ define <2 x float> @fdiv_splat_constant0(<2 x float> %x) {
define <2 x float> @fdiv_splat_constant1(<2 x float> %x) {
; CHECK-LABEL: @fdiv_splat_constant1(
-; CHECK-NEXT: [[TMP1:%.*]] = fdiv <2 x float> [[X:%.*]], <float 4.200000e+01, float 4.200000e+01>
+; CHECK-NEXT: [[TMP1:%.*]] = fdiv <2 x float> [[X:%.*]], <float 4.200000e+01, float undef>
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x float> [[TMP1]], <2 x float> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x float> [[R]]
;
@@ -896,7 +896,7 @@ define <2 x float> @fdiv_splat_constant1(<2 x float> %x) {
define <2 x float> @frem_splat_constant0(<2 x float> %x) {
; CHECK-LABEL: @frem_splat_constant0(
-; CHECK-NEXT: [[TMP1:%.*]] = frem <2 x float> <float 4.200000e+01, float 4.200000e+01>, [[X:%.*]]
+; CHECK-NEXT: [[TMP1:%.*]] = frem <2 x float> <float 4.200000e+01, float undef>, [[X:%.*]]
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x float> [[TMP1]], <2 x float> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x float> [[R]]
;
@@ -907,7 +907,7 @@ define <2 x float> @frem_splat_constant0(<2 x float> %x) {
define <2 x float> @frem_splat_constant1(<2 x float> %x) {
; CHECK-LABEL: @frem_splat_constant1(
-; CHECK-NEXT: [[TMP1:%.*]] = frem <2 x float> [[X:%.*]], <float 4.200000e+01, float 4.200000e+01>
+; CHECK-NEXT: [[TMP1:%.*]] = frem <2 x float> [[X:%.*]], <float 4.200000e+01, float undef>
; CHECK-NEXT: [[R:%.*]] = shufflevector <2 x float> [[TMP1]], <2 x float> undef, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x float> [[R]]
;
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