Check InlineAsm clobbers in PPCCTRLoops

We don't need to reject all inline asm as using the counter register (most does
not). Only those that explicitly clobber the counter register need to prevent
the transformation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182191 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hal Finkel 2013-05-18 09:20:39 +00:00
parent 9f61e485e6
commit bf0bc3b2a2
2 changed files with 53 additions and 0 deletions

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@ -33,6 +33,7 @@
#include "llvm/Analysis/ScalarEvolutionExpander.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
@ -148,6 +149,20 @@ bool PPCCTRLoops::mightUseCTR(const Triple &TT, BasicBlock *BB) {
for (BasicBlock::iterator J = BB->begin(), JE = BB->end();
J != JE; ++J) {
if (CallInst *CI = dyn_cast<CallInst>(J)) {
if (InlineAsm *IA = dyn_cast<InlineAsm>(CI->getCalledValue())) {
// Inline ASM is okay, unless it clobbers the ctr register.
InlineAsm::ConstraintInfoVector CIV = IA->ParseConstraints();
for (unsigned i = 0, ie = CIV.size(); i < ie; ++i) {
InlineAsm::ConstraintInfo &C = CIV[i];
if (C.Type != InlineAsm::isInput)
for (unsigned j = 0, je = C.Codes.size(); j < je; ++j)
if (StringRef(C.Codes[j]).equals_lower("{ctr}"))
return true;
}
continue;
}
if (!TM)
return true;
const TargetLowering *TLI = TM->getTargetLowering();

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@ -0,0 +1,38 @@
target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v128:128:128-n32:64"
target triple = "powerpc64-unknown-freebsd10.0"
; RUN: llc < %s -march=ppc64 | FileCheck %s
define void @test1(i32 %c) nounwind {
entry:
br label %for.body
for.body: ; preds = %for.body, %entry
%i.01 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
call void asm sideeffect "", "~{r5}"() nounwind
%inc = add nsw i32 %i.01, 1
%exitcond = icmp eq i32 %inc, 2048
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
ret void
; CHECK: @test1
; CHECK: mtctr
}
define void @test2(i32 %c) nounwind {
entry:
br label %for.body
for.body: ; preds = %for.body, %entry
%i.01 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
call void asm sideeffect "", "~{ctr}"() nounwind
%inc = add nsw i32 %i.01, 1
%exitcond = icmp eq i32 %inc, 2048
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body
ret void
; CHECK: @test2
; CHECK-NOT: mtctr
}