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Add a puts optimization that converts puts() to putchar('\n').

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120398 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Anders Carlsson 2010-11-30 06:19:18 +00:00
parent 1d06295583
commit 303023d9ff
2 changed files with 45 additions and 3 deletions
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33
lib/Transforms/Scalar/SimplifyLibCalls.cpp
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@ -1345,6 +1345,34 @@ struct FPrintFOpt : public LibCallOptimization {
}
};
//===---------------------------------------===//
// 'puts' Optimizations
struct PutsOpt : public LibCallOptimization {
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// Require one fixed pointer argument and an integer/void result.
const FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() ||
!(FT->getReturnType()->isIntegerTy() ||
FT->getReturnType()->isVoidTy()))
return 0;
// Check for a constant string.
std::string Str;
if (!GetConstantStringInfo(CI->getArgOperand(0), Str))
return 0;
if (Str.empty()) {
// puts("") -> putchar('\n')
Value *Res = EmitPutChar(B.getInt32('\n'), B, TD);
if (CI->use_empty()) return CI;
return B.CreateIntCast(Res, CI->getType(), true);
}
return 0;
}
};
} // end anonymous namespace.
//===----------------------------------------------------------------------===//
@ -1370,6 +1398,7 @@ namespace {
// Formatting and IO Optimizations
SPrintFOpt SPrintF; PrintFOpt PrintF;
FWriteOpt FWrite; FPutsOpt FPuts; FPrintFOpt FPrintF;
PutsOpt Puts;
bool Modified; // This is only used by doInitialization.
public:
@ -1484,6 +1513,7 @@ void SimplifyLibCalls::InitOptimizations() {
Optimizations["fwrite"] = &FWrite;
Optimizations["fputs"] = &FPuts;
Optimizations["fprintf"] = &FPrintF;
Optimizations["puts"] = &Puts;
}
@ -2298,9 +2328,6 @@ bool SimplifyLibCalls::doInitialization(Module &M) {
// * pow(sqrt(x),y) -> pow(x,y*0.5)
// * pow(pow(x,y),z)-> pow(x,y*z)
//
// puts:
// * puts("") -> putchar('\n')
//
// round, roundf, roundl:
// * round(cnst) -> cnst'
//

15
test/Transforms/SimplifyLibCalls/Puts.ll Normal file
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@ -0,0 +1,15 @@
; Test that the PutsOptimizer works correctly
; RUN: opt < %s -simplify-libcalls -S | FileCheck %s
target datalayout = "-p:64:64:64"
@.str = private constant [1 x i8] zeroinitializer
declare i32 @puts(i8*)
define void @foo() {
entry:
; CHECK: call i32 @putchar(i32 10)
%call = call i32 @puts(i8* getelementptr inbounds ([1 x i8]* @.str, i32 0, i32 0))
ret void
}