Update InstCombine to transform aggregate stores into scalar stores.

Summary: This is a first step toward getting proper support for aggregate loads and stores.

Test Plan: Added unittests

Reviewers: reames, chandlerc

Reviewed By: chandlerc

Subscribers: majnemer, joker.eph, chandlerc, llvm-commits

Differential Revision: http://reviews.llvm.org/D7780

Patch by Amaury Sechet

From: Mehdi Amini <mehdi.amini@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232284 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Mehdi Amini 2015-03-14 22:19:33 +00:00
parent 18233dc596
commit 3af5418aa4
2 changed files with 59 additions and 0 deletions

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@ -818,6 +818,30 @@ static bool combineStoreToValueType(InstCombiner &IC, StoreInst &SI) {
return false;
}
static bool unpackStoreToAggregate(InstCombiner &IC, StoreInst &SI) {
// FIXME: We could probably with some care handle both volatile and atomic
// stores here but it isn't clear that this is important.
if (!SI.isSimple())
return false;
Value *V = SI.getValueOperand();
Type *T = V->getType();
if (!T->isAggregateType())
return false;
if (StructType *ST = dyn_cast<StructType>(T)) {
// If the struct only have one element, we unpack.
if (ST->getNumElements() == 1) {
V = IC.Builder->CreateExtractValue(V, 0);
combineStoreToNewValue(IC, SI, V);
return true;
}
}
return false;
}
/// equivalentAddressValues - Test if A and B will obviously have the same
/// value. This includes recognizing that %t0 and %t1 will have the same
/// value in code like this:
@ -867,6 +891,10 @@ Instruction *InstCombiner::visitStoreInst(StoreInst &SI) {
else if (StoreAlign == 0)
SI.setAlignment(EffectiveStoreAlign);
// Try to canonicalize the stored type.
if (unpackStoreToAggregate(*this, SI))
return EraseInstFromFunction(SI);
// Replace GEP indices if possible.
if (Instruction *NewGEPI = replaceGEPIdxWithZero(*this, Ptr, SI)) {
Worklist.Add(NewGEPI);

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@ -0,0 +1,31 @@
; RUN: opt -instcombine -S < %s | FileCheck %s
target datalayout = "e-i64:64-f80:128-n8:16:32:64"
target triple = "x86_64-unknown-linux-gnu"
%A__vtbl = type { i8*, i32 (%A*)* }
%A = type { %A__vtbl* }
@A__vtblZ = constant %A__vtbl { i8* null, i32 (%A*)* @A.foo }
declare i32 @A.foo(%A* nocapture %this)
declare i8* @allocmemory(i64)
define void @structA() {
body:
%0 = tail call i8* @allocmemory(i64 32)
%1 = bitcast i8* %0 to %A*
; CHECK: store %A__vtbl* @A__vtblZ
store %A { %A__vtbl* @A__vtblZ }, %A* %1, align 8
ret void
}
define void @structOfA() {
body:
%0 = tail call i8* @allocmemory(i64 32)
%1 = bitcast i8* %0 to { %A }*
; CHECK: store %A__vtbl* @A__vtblZ
store { %A } { %A { %A__vtbl* @A__vtblZ } }, { %A }* %1, align 8
ret void
}