[PATCH] D40650: [InstSimplify] Fold insertelement into undef if index is out of bounds
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Wed Dec 6 06:05:25 PST 2017
This revision was automatically updated to reflect the committed changes.
Closed by commit rL319894: [InstSimplify] Fold insertelement into undef if index is out of bounds (authored by igor.laevsky).
Changed prior to commit:
https://reviews.llvm.org/D40650?vs=125493&id=125721#toc
Repository:
rL LLVM
https://reviews.llvm.org/D40650
Files:
llvm/trunk/include/llvm/Analysis/ConstantFolding.h
llvm/trunk/include/llvm/Analysis/InstructionSimplify.h
llvm/trunk/lib/Analysis/InstructionSimplify.cpp
llvm/trunk/test/Transforms/InstSimplify/pr28725.ll
Index: llvm/trunk/lib/Analysis/InstructionSimplify.cpp
===================================================================
--- llvm/trunk/lib/Analysis/InstructionSimplify.cpp
+++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp
@@ -3827,6 +3827,28 @@
return ::SimplifyInsertValueInst(Agg, Val, Idxs, Q, RecursionLimit);
}
+Value *llvm::SimplifyInsertElementInst(Value *Vec, Value *Val, Value *Idx,
+ const SimplifyQuery &Q) {
+ // Try to constant fold.
+ auto *VecC = dyn_cast<Constant>(Vec);
+ auto *ValC = dyn_cast<Constant>(Val);
+ auto *IdxC = dyn_cast<Constant>(Idx);
+ if (VecC && ValC && IdxC)
+ return ConstantFoldInsertElementInstruction(VecC, ValC, IdxC);
+
+ // 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.
+
+ return nullptr;
+}
+
/// Given operands for an ExtractValueInst, see if we can fold the result.
/// If not, this returns null.
static Value *SimplifyExtractValueInst(Value *Agg, ArrayRef<unsigned> Idxs,
@@ -4695,6 +4717,12 @@
IV->getIndices(), Q);
break;
}
+ case Instruction::InsertElement: {
+ auto *IE = cast<InsertElementInst>(I);
+ Result = SimplifyInsertElementInst(IE->getOperand(0), IE->getOperand(1),
+ IE->getOperand(2), Q);
+ break;
+ }
case Instruction::ExtractValue: {
auto *EVI = cast<ExtractValueInst>(I);
Result = SimplifyExtractValueInst(EVI->getAggregateOperand(),
Index: llvm/trunk/include/llvm/Analysis/ConstantFolding.h
===================================================================
--- llvm/trunk/include/llvm/Analysis/ConstantFolding.h
+++ llvm/trunk/include/llvm/Analysis/ConstantFolding.h
@@ -102,6 +102,13 @@
Constant *ConstantFoldExtractValueInstruction(Constant *Agg,
ArrayRef<unsigned> Idxs);
+/// \brief Attempt to constant fold an insertelement instruction with the
+/// specified operands and indices. The constant result is returned if
+/// successful; if not, null is returned.
+Constant *ConstantFoldInsertElementInstruction(Constant *Val,
+ Constant *Elt,
+ Constant *Idx);
+
/// \brief Attempt to constant fold an extractelement instruction with the
/// specified operands and indices. The constant result is returned if
/// successful; if not, null is returned.
Index: llvm/trunk/include/llvm/Analysis/InstructionSimplify.h
===================================================================
--- llvm/trunk/include/llvm/Analysis/InstructionSimplify.h
+++ llvm/trunk/include/llvm/Analysis/InstructionSimplify.h
@@ -161,6 +161,10 @@
Value *SimplifyInsertValueInst(Value *Agg, Value *Val, ArrayRef<unsigned> Idxs,
const SimplifyQuery &Q);
+/// Given operands for an InsertElement, fold the result or return null.
+Value *SimplifyInsertElementInst(Value *Vec, Value *Elt, Value *Idx,
+ const SimplifyQuery &Q);
+
/// Given operands for an ExtractValueInst, fold the result or return null.
Value *SimplifyExtractValueInst(Value *Agg, ArrayRef<unsigned> Idxs,
const SimplifyQuery &Q);
Index: llvm/trunk/test/Transforms/InstSimplify/pr28725.ll
===================================================================
--- llvm/trunk/test/Transforms/InstSimplify/pr28725.ll
+++ llvm/trunk/test/Transforms/InstSimplify/pr28725.ll
@@ -1,13 +1,12 @@
; RUN: opt -S -instsimplify < %s | FileCheck %s
-target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
-target triple = "x86_64-pc-windows-msvc"
%S = type { i16, i32 }
define <2 x i16> @test1() {
entry:
%b = insertelement <2 x i16> <i16 undef, i16 0>, i16 extractvalue (%S select (i1 icmp eq (i16 extractelement (<2 x i16> bitcast (<1 x i32> <i32 1> to <2 x i16>), i32 0), i16 0), %S zeroinitializer, %S { i16 0, i32 1 }), 0), i32 0
ret <2 x i16> %b
}
+; InstCombine will be able to fold this into zeroinitializer
; CHECK-LABEL: @test1(
-; CHECK: ret <2 x i16> zeroinitializer
+; CHECK: ret <2 x i16> <i16 extractvalue (%S select (i1 icmp eq (i16 extractelement (<2 x i16> bitcast (<1 x i32> <i32 1> to <2 x i16>), i32 0), i16 0), %S zeroinitializer, %S { i16 0, i32 1 }), 0), i16 0>
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