[SimplifyLibCalls] Take size of int into consideration when emitting ldexp/ldexpf

When rewriting
  powf(2.0, itofp(x)) -> ldexpf(1.0, x)
  exp2(sitofp(x)) -> ldexp(1.0, sext(x))
  exp2(uitofp(x)) -> ldexp(1.0, zext(x))

the wrong type was used for the second argument in the ldexp/ldexpf
libc call, for target architectures with 16 bit "int" type.
The transform incorrectly used a bitcasted function pointer with
a 32-bit argument when emitting the ldexp/ldexpf call for such
targets.

The fault is solved by using the correct function prototype
in the call, by asking TargetLibraryInfo about the size of "int".
TargetLibraryInfo by default derives the size of the int type by
assuming that it is 16 bits for 16-bit architectures, and
32 bits otherwise. If this isn't true for a target it should be
possible to override that default in the TargetLibraryInfo
initializer.

Differential Revision: https://reviews.llvm.org/D99438

1 files changed, 12 insertions, 3 deletions

diff --git a/llvm/lib/Analysis/TargetLibraryInfo.cpp b/llvm/lib/Analysis/TargetLibraryInfo.cpp
index 05088c1..d078cce 100644
--- a/llvm/lib/Analysis/TargetLibraryInfo.cpp
+++ b/llvm/lib/Analysis/TargetLibraryInfo.cpp
@@ -151,6 +151,11 @@ static void initialize(TargetLibraryInfoImpl &TLI, const Triple &T,
   TLI.setShouldExtI32Return(ShouldExtI32Return);
   TLI.setShouldSignExtI32Param(ShouldSignExtI32Param);
 
+  // Let's assume by default that the size of int is 32 bits, unless the target
+  // is a 16-bit architecture because then it most likely is 16 bits. If that
+  // isn't true for a target those defaults should be overridden below.
+  TLI.setIntSize(T.isArch16Bit() ? 16 : 32);
+
   if (T.isAMDGPU())
     TLI.disableAllFunctions();
 
@@ -639,7 +644,8 @@ TargetLibraryInfoImpl::TargetLibraryInfoImpl(const Triple &T) {
 TargetLibraryInfoImpl::TargetLibraryInfoImpl(const TargetLibraryInfoImpl &TLI)
     : CustomNames(TLI.CustomNames), ShouldExtI32Param(TLI.ShouldExtI32Param),
       ShouldExtI32Return(TLI.ShouldExtI32Return),
-      ShouldSignExtI32Param(TLI.ShouldSignExtI32Param) {
+      ShouldSignExtI32Param(TLI.ShouldSignExtI32Param),
+      SizeOfInt(TLI.SizeOfInt) {
   memcpy(AvailableArray, TLI.AvailableArray, sizeof(AvailableArray));
   VectorDescs = TLI.VectorDescs;
   ScalarDescs = TLI.ScalarDescs;
@@ -649,7 +655,8 @@ TargetLibraryInfoImpl::TargetLibraryInfoImpl(TargetLibraryInfoImpl &&TLI)
     : CustomNames(std::move(TLI.CustomNames)),
       ShouldExtI32Param(TLI.ShouldExtI32Param),
       ShouldExtI32Return(TLI.ShouldExtI32Return),
-      ShouldSignExtI32Param(TLI.ShouldSignExtI32Param) {
+      ShouldSignExtI32Param(TLI.ShouldSignExtI32Param),
+      SizeOfInt(TLI.SizeOfInt) {
   std::move(std::begin(TLI.AvailableArray), std::end(TLI.AvailableArray),
             AvailableArray);
   VectorDescs = TLI.VectorDescs;
@@ -661,6 +668,7 @@ TargetLibraryInfoImpl &TargetLibraryInfoImpl::operator=(const TargetLibraryInfoI
   ShouldExtI32Param = TLI.ShouldExtI32Param;
   ShouldExtI32Return = TLI.ShouldExtI32Return;
   ShouldSignExtI32Param = TLI.ShouldSignExtI32Param;
+  SizeOfInt = TLI.SizeOfInt;
   memcpy(AvailableArray, TLI.AvailableArray, sizeof(AvailableArray));
   return *this;
 }
@@ -670,6 +678,7 @@ TargetLibraryInfoImpl &TargetLibraryInfoImpl::operator=(TargetLibraryInfoImpl &&
   ShouldExtI32Param = TLI.ShouldExtI32Param;
   ShouldExtI32Return = TLI.ShouldExtI32Return;
   ShouldSignExtI32Param = TLI.ShouldSignExtI32Param;
+  SizeOfInt = TLI.SizeOfInt;
   std::move(std::begin(TLI.AvailableArray), std::end(TLI.AvailableArray),
             AvailableArray);
   return *this;
@@ -1498,7 +1507,7 @@ bool TargetLibraryInfoImpl::isValidProtoForLibFunc(const FunctionType &FTy,
   case LibFunc_ldexpl:
     return (NumParams == 2 && FTy.getReturnType()->isFloatingPointTy() &&
             FTy.getReturnType() == FTy.getParamType(0) &&
-            FTy.getParamType(1)->isIntegerTy(32));
+            FTy.getParamType(1)->isIntegerTy(getIntSize()));
 
   case LibFunc_ffs:
   case LibFunc_ffsl: