instcombine: Migrate printf optimizations
This patch migrates the printf optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168604 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/SimplifyLibCalls.cpp b/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 27ccdc1..85de642 100644
--- a/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -102,6 +102,15 @@
return true;
}
+static bool callHasFloatingPointArgument(const CallInst *CI) {
+ for (CallInst::const_op_iterator it = CI->op_begin(), e = CI->op_end();
+ it != e; ++it) {
+ if ((*it)->getType()->isFloatingPointTy())
+ return true;
+ }
+ return false;
+}
+
//===----------------------------------------------------------------------===//
// Fortified Library Call Optimizations
//===----------------------------------------------------------------------===//
@@ -1312,6 +1321,94 @@
}
};
+//===----------------------------------------------------------------------===//
+// Formatting and IO Library Call Optimizations
+//===----------------------------------------------------------------------===//
+
+struct PrintFOpt : public LibCallOptimization {
+ Value *optimizeFixedFormatString(Function *Callee, CallInst *CI,
+ IRBuilder<> &B) {
+ // Check for a fixed format string.
+ StringRef FormatStr;
+ if (!getConstantStringInfo(CI->getArgOperand(0), FormatStr))
+ return 0;
+
+ // Empty format string -> noop.
+ if (FormatStr.empty()) // Tolerate printf's declared void.
+ return CI->use_empty() ? (Value*)CI :
+ ConstantInt::get(CI->getType(), 0);
+
+ // Do not do any of the following transformations if the printf return value
+ // is used, in general the printf return value is not compatible with either
+ // putchar() or puts().
+ if (!CI->use_empty())
+ return 0;
+
+ // printf("x") -> putchar('x'), even for '%'.
+ if (FormatStr.size() == 1) {
+ Value *Res = EmitPutChar(B.getInt32(FormatStr[0]), B, TD, TLI);
+ if (CI->use_empty() || !Res) return Res;
+ return B.CreateIntCast(Res, CI->getType(), true);
+ }
+
+ // printf("foo\n") --> puts("foo")
+ if (FormatStr[FormatStr.size()-1] == '\n' &&
+ FormatStr.find('%') == std::string::npos) { // no format characters.
+ // Create a string literal with no \n on it. We expect the constant merge
+ // pass to be run after this pass, to merge duplicate strings.
+ FormatStr = FormatStr.drop_back();
+ Value *GV = B.CreateGlobalString(FormatStr, "str");
+ Value *NewCI = EmitPutS(GV, B, TD, TLI);
+ return (CI->use_empty() || !NewCI) ?
+ NewCI :
+ ConstantInt::get(CI->getType(), FormatStr.size()+1);
+ }
+
+ // Optimize specific format strings.
+ // printf("%c", chr) --> putchar(chr)
+ if (FormatStr == "%c" && CI->getNumArgOperands() > 1 &&
+ CI->getArgOperand(1)->getType()->isIntegerTy()) {
+ Value *Res = EmitPutChar(CI->getArgOperand(1), B, TD, TLI);
+
+ if (CI->use_empty() || !Res) return Res;
+ return B.CreateIntCast(Res, CI->getType(), true);
+ }
+
+ // printf("%s\n", str) --> puts(str)
+ if (FormatStr == "%s\n" && CI->getNumArgOperands() > 1 &&
+ CI->getArgOperand(1)->getType()->isPointerTy()) {
+ return EmitPutS(CI->getArgOperand(1), B, TD, TLI);
+ }
+ return 0;
+ }
+
+ virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ // Require one fixed pointer argument and an integer/void result.
+ FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() ||
+ !(FT->getReturnType()->isIntegerTy() ||
+ FT->getReturnType()->isVoidTy()))
+ return 0;
+
+ if (Value *V = optimizeFixedFormatString(Callee, CI, B)) {
+ return V;
+ }
+
+ // printf(format, ...) -> iprintf(format, ...) if no floating point
+ // arguments.
+ if (TLI->has(LibFunc::iprintf) && !callHasFloatingPointArgument(CI)) {
+ Module *M = B.GetInsertBlock()->getParent()->getParent();
+ Constant *IPrintFFn =
+ M->getOrInsertFunction("iprintf", FT, Callee->getAttributes());
+ CallInst *New = cast<CallInst>(CI->clone());
+ New->setCalledFunction(IPrintFFn);
+ B.Insert(New);
+ return New;
+ }
+ return 0;
+ }
+};
+
} // End anonymous namespace.
namespace llvm {
@@ -1365,6 +1462,9 @@
IsAsciiOpt IsAscii;
ToAsciiOpt ToAscii;
+ // Formatting and IO library call optimizations.
+ PrintFOpt PrintF;
+
void initOptimizations();
void addOpt(LibFunc::Func F, LibCallOptimization* Opt);
void addOpt(LibFunc::Func F1, LibFunc::Func F2, LibCallOptimization* Opt);
@@ -1485,6 +1585,9 @@
addOpt(LibFunc::isdigit, &IsDigit);
addOpt(LibFunc::isascii, &IsAscii);
addOpt(LibFunc::toascii, &ToAscii);
+
+ // Formatting and IO library call optimizations.
+ addOpt(LibFunc::printf, &PrintF);
}
Value *LibCallSimplifierImpl::optimizeCall(CallInst *CI) {