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[AArch64] Fix sext/zext folding in address arithmetic. 

We were accidentally folding a sign/zero extend in to address arithmetic in a different BB when the extend wasn't available there.

Cross BB fast-isel isn't safe, so restrict this to only when the extend is in the same BB as the use.

llvm-svn: 236764
This commit is contained in:
Pete Cooper 2015-05-07 19:21:36 +00:00
parent 841ee9b998
commit f52123b454
2 changed files with 71 additions and 29 deletions
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61
llvm/lib/Target/AArch64/AArch64FastISel.cpp
View File

@ -664,20 +664,22 @@ bool AArch64FastISel::computeAddress(const Value *Obj, Address &Addr, Type *Ty)
Addr.setExtendType(AArch64_AM::LSL);
const Value *Src = U->getOperand(0);
if (const auto *I = dyn_cast<Instruction>(Src))
if (FuncInfo.MBBMap[I->getParent()] == FuncInfo.MBB)
Src = I;
// Fold the zext or sext when it won't become a noop.
if (const auto *ZE = dyn_cast<ZExtInst>(Src)) {
if (!isIntExtFree(ZE) && ZE->getOperand(0)->getType()->isIntegerTy(32)) {
Addr.setExtendType(AArch64_AM::UXTW);
Src = ZE->getOperand(0);
}
} else if (const auto *SE = dyn_cast<SExtInst>(Src)) {
if (!isIntExtFree(SE) && SE->getOperand(0)->getType()->isIntegerTy(32)) {
Addr.setExtendType(AArch64_AM::SXTW);
Src = SE->getOperand(0);
if (const auto *I = dyn_cast<Instruction>(Src)) {
if (FuncInfo.MBBMap[I->getParent()] == FuncInfo.MBB) {
// Fold the zext or sext when it won't become a noop.
if (const auto *ZE = dyn_cast<ZExtInst>(I)) {
if (!isIntExtFree(ZE) &&
ZE->getOperand(0)->getType()->isIntegerTy(32)) {
Addr.setExtendType(AArch64_AM::UXTW);
Src = ZE->getOperand(0);
}
} else if (const auto *SE = dyn_cast<SExtInst>(I)) {
if (!isIntExtFree(SE) &&
SE->getOperand(0)->getType()->isIntegerTy(32)) {
Addr.setExtendType(AArch64_AM::SXTW);
Src = SE->getOperand(0);
}
}
}
}
@ -746,21 +748,22 @@ bool AArch64FastISel::computeAddress(const Value *Obj, Address &Addr, Type *Ty)
Addr.setExtendType(AArch64_AM::LSL);
const Value *Src = LHS;
if (const auto *I = dyn_cast<Instruction>(Src))
if (FuncInfo.MBBMap[I->getParent()] == FuncInfo.MBB)
Src = I;
// Fold the zext or sext when it won't become a noop.
if (const auto *ZE = dyn_cast<ZExtInst>(Src)) {
if (!isIntExtFree(ZE) && ZE->getOperand(0)->getType()->isIntegerTy(32)) {
Addr.setExtendType(AArch64_AM::UXTW);
Src = ZE->getOperand(0);
}
} else if (const auto *SE = dyn_cast<SExtInst>(Src)) {
if (!isIntExtFree(SE) && SE->getOperand(0)->getType()->isIntegerTy(32)) {
Addr.setExtendType(AArch64_AM::SXTW);
Src = SE->getOperand(0);
if (const auto *I = dyn_cast<Instruction>(Src)) {
if (FuncInfo.MBBMap[I->getParent()] == FuncInfo.MBB) {
// Fold the zext or sext when it won't become a noop.
if (const auto *ZE = dyn_cast<ZExtInst>(I)) {
if (!isIntExtFree(ZE) &&
ZE->getOperand(0)->getType()->isIntegerTy(32)) {
Addr.setExtendType(AArch64_AM::UXTW);
Src = ZE->getOperand(0);
}
} else if (const auto *SE = dyn_cast<SExtInst>(I)) {
if (!isIntExtFree(SE) &&
SE->getOperand(0)->getType()->isIntegerTy(32)) {
Addr.setExtendType(AArch64_AM::SXTW);
Src = SE->getOperand(0);
}
}
}
}

39
llvm/test/CodeGen/AArch64/fast-isel-address-extends.ll Normal file
View File

@ -0,0 +1,39 @@
; RUN: llc %s -o - -O0 -verify-machineinstrs -fast-isel=true | FileCheck %s
target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
target triple = "arm64-apple-ios8.0.0"
; This test was trying to fold the sext %tmp142 in to the address arithmetic in %sunkaddr1.
; This was incorrect as %.mux isn't available in the last bb.
; CHECK: sxtw [[REG:x[0-9]+]]
; CHECK: strh wzr, {{\[}}[[REG]], {{.*}}, lsl #1]
; Function Attrs: nounwind optsize ssp
define void @EdgeLoop(i32 %dir, i32 %edge, i32 %width, i16* %tmp89, i32 %tmp136, i16 %tmp144) #0 {
bb:
%tmp2 = icmp eq i32 %dir, 0
%.mux = select i1 %tmp2, i32 %width, i32 1
%tmp142 = sext i32 %.mux to i64
%tmp151 = shl nsw i64 %tmp142, 1
%tmp153 = getelementptr inbounds i16, i16* %tmp89, i64 %tmp151
%tmp154 = load i16, i16* %tmp153, align 2
%tmp155 = zext i16 %tmp154 to i32
br i1 %tmp2, label %bb225, label %bb212
bb212: ; preds = %bb
store i16 %tmp144, i16* %tmp89, align 2
ret void
bb225: ; preds = %bb
%tmp248 = trunc i32 %tmp155 to i16
store i16 %tmp248, i16* %tmp89, align 2
%sunkaddr = ptrtoint i16* %tmp89 to i64
%sunkaddr1 = mul i64 %tmp142, 2
%sunkaddr2 = add i64 %sunkaddr, %sunkaddr1
%sunkaddr3 = inttoptr i64 %sunkaddr2 to i16*
store i16 0, i16* %sunkaddr3, align 2
ret void
}
attributes #0 = { nounwind optsize ssp }