instcombine: Migrate ffs* optimizations
This patch migrates the ffs* optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168571 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/SimplifyLibCalls.cpp b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
index 8f31cd1..fbfb7b4 100644
--- a/lib/Transforms/Scalar/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
@@ -19,7 +19,6 @@
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/BuildLibCalls.h"
#include "llvm/IRBuilder.h"
-#include "llvm/Intrinsics.h"
#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
@@ -101,42 +100,6 @@
//===----------------------------------------------------------------------===//
//===---------------------------------------===//
-// 'ffs*' Optimizations
-
-struct FFSOpt : public LibCallOptimization {
- virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
- FunctionType *FT = Callee->getFunctionType();
- // Just make sure this has 2 arguments of the same FP type, which match the
- // result type.
- if (FT->getNumParams() != 1 ||
- !FT->getReturnType()->isIntegerTy(32) ||
- !FT->getParamType(0)->isIntegerTy())
- return 0;
-
- Value *Op = CI->getArgOperand(0);
-
- // Constant fold.
- if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
- if (CI->isZero()) // ffs(0) -> 0.
- return B.getInt32(0);
- // ffs(c) -> cttz(c)+1
- return B.getInt32(CI->getValue().countTrailingZeros() + 1);
- }
-
- // ffs(x) -> x != 0 ? (i32)llvm.cttz(x)+1 : 0
- Type *ArgType = Op->getType();
- Value *F = Intrinsic::getDeclaration(Callee->getParent(),
- Intrinsic::cttz, ArgType);
- Value *V = B.CreateCall2(F, Op, B.getFalse(), "cttz");
- V = B.CreateAdd(V, ConstantInt::get(V->getType(), 1));
- V = B.CreateIntCast(V, B.getInt32Ty(), false);
-
- Value *Cond = B.CreateICmpNE(Op, Constant::getNullValue(ArgType));
- return B.CreateSelect(Cond, V, B.getInt32(0));
- }
-};
-
-//===---------------------------------------===//
// 'isdigit' Optimizations
struct IsDigitOpt : public LibCallOptimization {
@@ -579,7 +542,7 @@
StringMap<LibCallOptimization*> Optimizations;
// Integer Optimizations
- FFSOpt FFS; AbsOpt Abs; IsDigitOpt IsDigit; IsAsciiOpt IsAscii;
+ AbsOpt Abs; IsDigitOpt IsDigit; IsAsciiOpt IsAscii;
ToAsciiOpt ToAscii;
// Formatting and IO Optimizations
SPrintFOpt SPrintF; PrintFOpt PrintF;
@@ -640,9 +603,6 @@
/// we know.
void SimplifyLibCalls::InitOptimizations() {
// Integer Optimizations
- Optimizations["ffs"] = &FFS;
- Optimizations["ffsl"] = &FFS;
- Optimizations["ffsll"] = &FFS;
Optimizations["abs"] = &Abs;
Optimizations["labs"] = &Abs;
Optimizations["llabs"] = &Abs;
diff --git a/lib/Transforms/Utils/SimplifyLibCalls.cpp b/lib/Transforms/Utils/SimplifyLibCalls.cpp
index cceec66..dd623dc 100644
--- a/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -20,6 +20,7 @@
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Function.h"
#include "llvm/IRBuilder.h"
+#include "llvm/Intrinsics.h"
#include "llvm/Module.h"
#include "llvm/LLVMContext.h"
#include "llvm/Target/TargetLibraryInfo.h"
@@ -1212,6 +1213,43 @@
}
};
+//===----------------------------------------------------------------------===//
+// Integer Library Call Optimizations
+//===----------------------------------------------------------------------===//
+
+struct FFSOpt : public LibCallOptimization {
+ virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+ FunctionType *FT = Callee->getFunctionType();
+ // Just make sure this has 2 arguments of the same FP type, which match the
+ // result type.
+ if (FT->getNumParams() != 1 ||
+ !FT->getReturnType()->isIntegerTy(32) ||
+ !FT->getParamType(0)->isIntegerTy())
+ return 0;
+
+ Value *Op = CI->getArgOperand(0);
+
+ // Constant fold.
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
+ if (CI->isZero()) // ffs(0) -> 0.
+ return B.getInt32(0);
+ // ffs(c) -> cttz(c)+1
+ return B.getInt32(CI->getValue().countTrailingZeros() + 1);
+ }
+
+ // ffs(x) -> x != 0 ? (i32)llvm.cttz(x)+1 : 0
+ Type *ArgType = Op->getType();
+ Value *F = Intrinsic::getDeclaration(Callee->getParent(),
+ Intrinsic::cttz, ArgType);
+ Value *V = B.CreateCall2(F, Op, B.getFalse(), "cttz");
+ V = B.CreateAdd(V, ConstantInt::get(V->getType(), 1));
+ V = B.CreateIntCast(V, B.getInt32Ty(), false);
+
+ Value *Cond = B.CreateICmpNE(Op, Constant::getNullValue(ArgType));
+ return B.CreateSelect(Cond, V, B.getInt32(0));
+ }
+};
+
} // End anonymous namespace.
namespace llvm {
@@ -1258,6 +1296,9 @@
UnaryDoubleFPOpt UnaryDoubleFP, UnsafeUnaryDoubleFP;
CosOpt Cos; PowOpt Pow; Exp2Opt Exp2;
+ // Integer library call optimizations.
+ FFSOpt FFS;
+
void initOptimizations();
void addOpt(LibFunc::Func F, LibCallOptimization* Opt);
void addOpt(LibFunc::Func F1, LibFunc::Func F2, LibCallOptimization* Opt);
@@ -1367,6 +1408,11 @@
Optimizations["llvm.exp2.f80"] = &Exp2;
Optimizations["llvm.exp2.f64"] = &Exp2;
Optimizations["llvm.exp2.f32"] = &Exp2;
+
+ // Integer library call optimizations.
+ addOpt(LibFunc::ffs, &FFS);
+ addOpt(LibFunc::ffsl, &FFS);
+ addOpt(LibFunc::ffsll, &FFS);
}
Value *LibCallSimplifierImpl::optimizeCall(CallInst *CI) {