SimplifyLibCalls: When emitting an overloaded fp function check that it's available.

The existing code missed some edge cases when e.g. we're going to emit sqrtf but
only the availability of sqrt was checked. This happens on odd platforms like
windows.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189724 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 43 insertions, 3 deletions

diff --git a/lib/Transforms/Utils/SimplifyLibCalls.cpp b/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 83636fbb5a..4e7055b0ca 100644
--- a/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -118,6 +118,21 @@ static bool callHasFloatingPointArgument(const CallInst *CI) {
   return false;
 }
 
+/// \brief Check whether the overloaded unary floating point function
+/// corresponing to \a Ty is available.
+static bool hasUnaryFloatFn(const TargetLibraryInfo *TLI, Type *Ty,
+                            LibFunc::Func DoubleFn, LibFunc::Func FloatFn,
+                            LibFunc::Func LongDoubleFn) {
+  switch (Ty->getTypeID()) {
+  case Type::FloatTyID:
+    return TLI->has(FloatFn);
+  case Type::DoubleTyID:
+    return TLI->has(DoubleFn);
+  default:
+    return TLI->has(LongDoubleFn);
+  }
+}
+
 //===----------------------------------------------------------------------===//
 // Fortified Library Call Optimizations
 //===----------------------------------------------------------------------===//
@@ -1137,7 +1152,9 @@ struct PowOpt : public UnsafeFPLibCallOptimization {
       if (Op1C->isExactlyValue(1.0))
         return Op1C;
       // pow(2.0, x) -> exp2(x)
-      if (Op1C->isExactlyValue(2.0) && TLI->has(LibFunc::exp2))
+      if (Op1C->isExactlyValue(2.0) &&
+          hasUnaryFloatFn(TLI, Op1->getType(), LibFunc::exp2, LibFunc::exp2f,
+                          LibFunc::exp2l))
         return EmitUnaryFloatFnCall(Op2, "exp2", B, Callee->getAttributes());
     }
 
@@ -1148,7 +1165,10 @@ struct PowOpt : public UnsafeFPLibCallOptimization {
       return ConstantFP::get(CI->getType(), 1.0);
 
     if (Op2C->isExactlyValue(0.5) &&
-        TLI->has(LibFunc::sqrt) && TLI->has(LibFunc::fabs)) {
+        hasUnaryFloatFn(TLI, Op2->getType(), LibFunc::sqrt, LibFunc::sqrtf,
+                        LibFunc::sqrtl) &&
+        hasUnaryFloatFn(TLI, Op2->getType(), LibFunc::fabs, LibFunc::fabsf,
+                        LibFunc::fabsl)) {
       // Expand pow(x, 0.5) to (x == -infinity ? +infinity : fabs(sqrt(x))).
       // This is faster than calling pow, and still handles negative zero
       // and negative infinity correctly.
@@ -1181,7 +1201,7 @@ struct Exp2Opt : public UnsafeFPLibCallOptimization {
   virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
     Value *Ret = NULL;
     if (UnsafeFPShrink && Callee->getName() == "exp2" &&
-        TLI->has(LibFunc::exp2)) {
+        TLI->has(LibFunc::exp2f)) {
       UnaryDoubleFPOpt UnsafeUnaryDoubleFP(true);
       Ret = UnsafeUnaryDoubleFP.callOptimizer(Callee, CI, B);
     }
diff --git a/test/Transforms/InstCombine/win-math.ll b/test/Transforms/InstCombine/win-math.ll
index df3ac934a7..e6e79e2b84 100644
--- a/test/Transforms/InstCombine/win-math.ll
+++ b/test/Transforms/InstCombine/win-math.ll
@@ -273,3 +273,23 @@ define float @float_round(float %x) nounwind readnone {
     ret float %3
 }
 
+declare float @powf(float, float)
+; win32 lacks sqrtf&fabsf, win64 lacks fabsf
+define float @float_powsqrt(float %x) nounwind readnone {
+; WIN32-LABEL: @float_powsqrt(
+; WIN32-NOT: float @sqrtf
+; WIN32: float @powf
+; WIN64-LABEL: @float_powsqrt(
+; WIN64-NOT: float @sqrtf
+; WIN64: float @powf
+; MINGW32-LABEL: @float_powsqrt(
+; MINGW32: float @sqrtf
+; MINGW32: float @fabsf
+; MINGW32-NOT: float @powf
+; MINGW64-LABEL: @float_powsqrt(
+; MINGW64: float @sqrtf
+; MINGW64: float @fabsf
+; MINGW64-NOT: float @powf
+    %1 = call float @powf(float %x, float 0.5)
+    ret float %1
+}