[llvm] r321575 - [instsimplify] consistently handle undef and out of bound indices for insertelement and extractelement
Philip Reames via llvm-commits
llvm-commits at lists.llvm.org
Fri Dec 29 21:54:22 PST 2017
Author: reames
Date: Fri Dec 29 21:54:22 2017
New Revision: 321575
URL: http://llvm.org/viewvc/llvm-project?rev=321575&view=rev
Log:
[instsimplify] consistently handle undef and out of bound indices for insertelement and extractelement
In one case, we were handling out of bounds, but not undef indices. In the other, we were handling undef (with the comment making the analogy to out of bounds), but not out of bounds. Be consistent and treat both undef and constant out of bounds indices as producing undefined results.
As a side effect, this also protects instcombine from having to handle large constant indices as we always simplify first.
Modified:
llvm/trunk/lib/Analysis/InstructionSimplify.cpp
llvm/trunk/test/Transforms/InstCombine/extractelement.ll
llvm/trunk/test/Transforms/InstCombine/vec_demanded_elts.ll
llvm/trunk/test/Transforms/InstCombine/vector_insertelt_shuffle.ll
llvm/trunk/test/Transforms/InstSimplify/extract-element.ll
llvm/trunk/test/Transforms/InstSimplify/insertelement.ll
Modified: llvm/trunk/lib/Analysis/InstructionSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InstructionSimplify.cpp?rev=321575&r1=321574&r2=321575&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/InstructionSimplify.cpp (original)
+++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp Fri Dec 29 21:54:22 2017
@@ -3838,12 +3838,13 @@ Value *llvm::SimplifyInsertElementInst(V
// Fold into undef if index is out of bounds.
if (auto *CI = dyn_cast<ConstantInt>(Idx)) {
uint64_t NumElements = cast<VectorType>(Vec->getType())->getNumElements();
-
if (CI->uge(NumElements))
return UndefValue::get(Vec->getType());
}
- // TODO: We should also fold if index is iteslf an undef.
+ // If index is undef, it might be out of bounds (see above case)
+ if (isa<UndefValue>(Idx))
+ return UndefValue::get(Vec->getType());
return nullptr;
}
@@ -3896,10 +3897,13 @@ static Value *SimplifyExtractElementInst
// If extracting a specified index from the vector, see if we can recursively
// find a previously computed scalar that was inserted into the vector.
- if (auto *IdxC = dyn_cast<ConstantInt>(Idx))
- if (IdxC->getValue().ule(Vec->getType()->getVectorNumElements()))
- if (Value *Elt = findScalarElement(Vec, IdxC->getZExtValue()))
- return Elt;
+ if (auto *IdxC = dyn_cast<ConstantInt>(Idx)) {
+ if (IdxC->getValue().uge(Vec->getType()->getVectorNumElements()))
+ // definitely out of bounds, thus undefined result
+ return UndefValue::get(Vec->getType()->getVectorElementType());
+ if (Value *Elt = findScalarElement(Vec, IdxC->getZExtValue()))
+ return Elt;
+ }
// An undef extract index can be arbitrarily chosen to be an out-of-range
// index value, which would result in the instruction being undef.
Modified: llvm/trunk/test/Transforms/InstCombine/extractelement.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/extractelement.ll?rev=321575&r1=321574&r2=321575&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/extractelement.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/extractelement.ll Fri Dec 29 21:54:22 2017
@@ -3,8 +3,7 @@
define i32 @extractelement_out_of_range(<2 x i32> %x) {
; CHECK-LABEL: @extractelement_out_of_range(
-; CHECK-NEXT: [[E1:%.*]] = extractelement <2 x i32> [[X:%.*]], i8 16
-; CHECK-NEXT: ret i32 [[E1]]
+; CHECK-NEXT: ret i32 undef
;
%E1 = extractelement <2 x i32> %x, i8 16
ret i32 %E1
Modified: llvm/trunk/test/Transforms/InstCombine/vec_demanded_elts.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/vec_demanded_elts.ll?rev=321575&r1=321574&r2=321575&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/vec_demanded_elts.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/vec_demanded_elts.ll Fri Dec 29 21:54:22 2017
@@ -191,11 +191,11 @@ define <4 x i32> @inselt_shuf_no_demand_
define <4 x float> @inselt_shuf_no_demand_bogus_insert_index_in_chain(float %a1, float %a2, float %a3, i32 %variable_index) {
; CHECK-LABEL: @inselt_shuf_no_demand_bogus_insert_index_in_chain(
-; CHECK-NEXT: [[OUT1:%.*]] = insertelement <4 x float> undef, float %a1, i32 1
-; CHECK-NEXT: ret <4 x float> [[OUT1]]
+; CHECK-NEXT: [[OUT12:%.*]] = insertelement <4 x float> undef, float [[A2:%.*]], i32 [[VARIABLE_INDEX:%.*]]
+; CHECK-NEXT: ret <4 x float> [[OUT12]]
;
%out1 = insertelement <4 x float> undef, float %a1, i32 1
- %out12 = insertelement <4 x float> %out1, float %a2, i32 undef ; something unexpected
+ %out12 = insertelement <4 x float> %out1, float %a2, i32 %variable_index ; something unexpected
%out123 = insertelement <4 x float> %out12, float %a3, i32 3
%shuffle = shufflevector <4 x float> %out123, <4 x float> undef, <4 x i32> <i32 0, i32 undef, i32 undef, i32 undef>
ret <4 x float> %shuffle
Modified: llvm/trunk/test/Transforms/InstCombine/vector_insertelt_shuffle.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/vector_insertelt_shuffle.ll?rev=321575&r1=321574&r2=321575&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/vector_insertelt_shuffle.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/vector_insertelt_shuffle.ll Fri Dec 29 21:54:22 2017
@@ -66,9 +66,7 @@ define <4 x float> @bazzz(<4 x float> %x
define <4 x float> @bazzzz(<4 x float> %x) {
; CHECK-LABEL: @bazzzz(
-; CHECK-NEXT: [[INS1:%.*]] = insertelement <4 x float> %x, float 1.000000e+00, i32 undef
-; CHECK-NEXT: [[INS2:%.*]] = insertelement <4 x float> %x, float 2.000000e+00, i32 2
-; CHECK-NEXT: ret <4 x float> [[INS2]]
+; CHECK-NEXT: ret <4 x float> <float undef, float undef, float 2.000000e+00, float undef>
;
%ins1 = insertelement<4 x float> %x, float 1.0, i32 undef
%ins2 = insertelement<4 x float> %ins1, float 2.0, i32 2
Modified: llvm/trunk/test/Transforms/InstSimplify/extract-element.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/extract-element.ll?rev=321575&r1=321574&r2=321575&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstSimplify/extract-element.ll (original)
+++ llvm/trunk/test/Transforms/InstSimplify/extract-element.ll Fri Dec 29 21:54:22 2017
@@ -5,9 +5,43 @@
define i129 @vec_extract_negidx(<3 x i129> %a) {
; CHECK-LABEL: @vec_extract_negidx(
-; CHECK-NEXT: [[E1:%.*]] = extractelement <3 x i129> [[A:%.*]], i129 -1
-; CHECK-NEXT: ret i129 [[E1]]
+; CHECK-NEXT: ret i129 undef
;
%E1 = extractelement <3 x i129> %a, i129 -1
ret i129 %E1
}
+
+define i129 @vec_extract_out_of_bounds(<3 x i129> %a) {
+; CHECK-LABEL: @vec_extract_out_of_bounds(
+; CHECK-NEXT: ret i129 undef
+;
+ %E1 = extractelement <3 x i129> %a, i129 3
+ ret i129 %E1
+}
+
+define i129 @vec_extract_out_of_bounds2(<3 x i129> %a) {
+; CHECK-LABEL: @vec_extract_out_of_bounds2(
+; CHECK-NEXT: ret i129 undef
+;
+ %E1 = extractelement <3 x i129> %a, i129 999999999999999
+ ret i129 %E1
+}
+
+
+define i129 @vec_extract_undef_index(<3 x i129> %a) {
+; CHECK-LABEL: @vec_extract_undef_index(
+; CHECK-NEXT: ret i129 undef
+;
+ %E1 = extractelement <3 x i129> %a, i129 undef
+ ret i129 %E1
+}
+
+
+define i129 @vec_extract_in_bounds(<3 x i129> %a) {
+; CHECK-LABEL: @vec_extract_in_bounds(
+; CHECK-NEXT: %E1 = extractelement <3 x i129> %a, i129 2
+; CHECK-NEXT: ret i129 %E1
+;
+ %E1 = extractelement <3 x i129> %a, i129 2
+ ret i129 %E1
+}
Modified: llvm/trunk/test/Transforms/InstSimplify/insertelement.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/insertelement.ll?rev=321575&r1=321574&r2=321575&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstSimplify/insertelement.ll (original)
+++ llvm/trunk/test/Transforms/InstSimplify/insertelement.ll Fri Dec 29 21:54:22 2017
@@ -23,3 +23,9 @@ define <4 x i32> @test4(<4 x i32> %A) {
; CHECK: ret <4 x i32> undef
ret <4 x i32> %I
}
+
+define <4 x i32> @test5(<4 x i32> %A) {
+ %I = insertelement <4 x i32> %A, i32 5, i64 undef
+ ; CHECK: ret <4 x i32> undef
+ ret <4 x i32> %I
+}
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