// Integer Library Call Optimizations
Value *optimizeFFS(CallInst *CI, IRBuilder<> &B);
+ Value *optimizeFls(CallInst *CI, IRBuilder<> &B);
Value *optimizeAbs(CallInst *CI, IRBuilder<> &B);
Value *optimizeIsDigit(CallInst *CI, IRBuilder<> &B);
Value *optimizeIsAscii(CallInst *CI, IRBuilder<> &B);
case LibFunc::ffs:
case LibFunc::ffsl:
case LibFunc::ffsll:
+ case LibFunc::fls:
+ case LibFunc::flsl:
+ case LibFunc::flsll:
return (NumParams == 1 && FTy.getReturnType()->isIntegerTy(32) &&
FTy.getParamType(0)->isIntegerTy());
return (NumParams == 1 && FTy.getReturnType()->isIntegerTy(32) &&
FTy.getReturnType() == FTy.getParamType(0));
- case LibFunc::fls:
- case LibFunc::flsl:
- case LibFunc::flsll:
case LibFunc::abs:
case LibFunc::labs:
case LibFunc::llabs:
return B.CreateSelect(Cond, V, B.getInt32(0));
}
+Value *LibCallSimplifier::optimizeFls(CallInst *CI, IRBuilder<> &B) {
+ // fls(x) -> (i32)(sizeInBits(x) - llvm.ctlz(x, false))
+ Value *Op = CI->getArgOperand(0);
+ Type *ArgType = Op->getType();
+ Value *F = Intrinsic::getDeclaration(CI->getCalledFunction()->getParent(),
+ Intrinsic::ctlz, ArgType);
+ Value *V = B.CreateCall(F, {Op, B.getFalse()}, "ctlz");
+ V = B.CreateSub(ConstantInt::get(V->getType(), ArgType->getIntegerBitWidth()),
+ V);
+ return B.CreateIntCast(V, CI->getType(), false);
+}
+
Value *LibCallSimplifier::optimizeAbs(CallInst *CI, IRBuilder<> &B) {
// abs(x) -> x >s -1 ? x : -x
Value *Op = CI->getArgOperand(0);
case LibFunc::ffsl:
case LibFunc::ffsll:
return optimizeFFS(CI, Builder);
+ case LibFunc::fls:
+ case LibFunc::flsl:
+ case LibFunc::flsll:
+ return optimizeFls(CI, Builder);
case LibFunc::abs:
case LibFunc::labs:
case LibFunc::llabs:
--- /dev/null
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target triple = "x86_64-unknown-freebsd11.0"
+
+
+; CHECK-LABEL: define i32 @myfls(
+; CHECK: ret i32 6
+; CHECK: }
+
+define i32 @myfls() {
+entry:
+ %call = call i32 @fls(i32 42)
+ ret i32 %call
+}
+
+; CHECK-LABEL: define i32 @myflsl(
+; CHECK: ret i32 6
+; CHECK: }
+
+define i32 @myflsl() {
+ %patatino = call i32 @flsl(i64 42)
+ ret i32 %patatino
+}
+
+; CHECK-LABEL: define i32 @myflsll(
+; CHECK: ret i32 6
+; CHECK: }
+
+define i32 @myflsll() {
+ %whatever = call i32 @flsll(i64 42)
+ ret i32 %whatever
+}
+
+; Lower to llvm.ctlz() if the argument is not a constant
+; CHECK-LABEL: define i32 @flsnotconst(
+; CHECK-NEXT: %ctlz = call i64 @llvm.ctlz.i64(i64 %z, i1 false)
+; CHECK-NEXT: %1 = sub nsw i64 64, %ctlz
+; CHECK-NEXT: %2 = trunc i64 %1 to i32
+; CHECK-NEXT: ret i32 %2
+
+define i32 @flsnotconst(i64 %z) {
+ %goo = call i32 @flsl(i64 %z)
+ ret i32 %goo
+}
+
+declare i32 @fls(i32)
+declare i32 @flsl(i64)
+declare i32 @flsll(i64)