[NVPTX] Infer __nvvm_reflect as nounwind, readnone

This patch simply mirrors the attributes we give to @llvm.nvvm.reflect
to the __nvvm_reflect libdevice call.  This shaves about 30% of the code
in libdevice away because of CSE opportunities.  It's also helps us
figure out that libdevice implementations of transcendental functions
don't have side-effects.

llvm-svn: 265060

diff --git a/llvm/include/llvm/Analysis/TargetLibraryInfo.def b/llvm/include/llvm/Analysis/TargetLibraryInfo.def
index 7798e3c..b2a593d 100644 (file)
--- a/llvm/include/llvm/Analysis/TargetLibraryInfo.def
+++ b/llvm/include/llvm/Analysis/TargetLibraryInfo.def
@@ -195,6 +195,11 @@ TLI_DEFINE_STRING_INTERNAL("__memmove_chk")
 /// void *__memset_chk(void *s, char v, size_t n, size_t s1size);
 TLI_DEFINE_ENUM_INTERNAL(memset_chk)
 TLI_DEFINE_STRING_INTERNAL("__memset_chk")
+
+// int __nvvm_reflect(const char *)
+TLI_DEFINE_ENUM_INTERNAL(nvvm_reflect)
+TLI_DEFINE_STRING_INTERNAL("__nvvm_reflect")
+
 /// double __sincospi_stret(double x);
 TLI_DEFINE_ENUM_INTERNAL(sincospi_stret)
 TLI_DEFINE_STRING_INTERNAL("__sincospi_stret")

diff --git a/llvm/lib/Analysis/TargetLibraryInfo.cpp b/llvm/lib/Analysis/TargetLibraryInfo.cpp
index 3bd54c4..ab667ab 100644 (file)
--- a/llvm/lib/Analysis/TargetLibraryInfo.cpp
+++ b/llvm/lib/Analysis/TargetLibraryInfo.cpp
@@ -396,8 +396,12 @@ static void initialize(TargetLibraryInfoImpl &TLI, const Triple &T,
   //
   // FIXME: Having no standard library prevents e.g. many fastmath
   // optimizations, so this situation should be fixed.
-  if (T.isNVPTX())
+  if (T.isNVPTX()) {
     TLI.disableAllFunctions();
+    TLI.setAvailable(LibFunc::nvvm_reflect);
+  } else {
+    TLI.setUnavailable(LibFunc::nvvm_reflect);
+  }
 
   TLI.addVectorizableFunctionsFromVecLib(ClVectorLibrary);
 }

diff --git a/llvm/lib/Transforms/IPO/InferFunctionAttrs.cpp b/llvm/lib/Transforms/IPO/InferFunctionAttrs.cpp
index 16922ab..030a646 100644 (file)
--- a/llvm/lib/Transforms/IPO/InferFunctionAttrs.cpp
+++ b/llvm/lib/Transforms/IPO/InferFunctionAttrs.cpp
@@ -924,6 +924,15 @@ static bool inferPrototypeAttributes(Function &F,
     Changed |= setOnlyReadsMemory(F, 2);
     return Changed;
 
+  // int __nvvm_reflect(const char *)
+  case LibFunc::nvvm_reflect:
+    if (FTy->getNumParams() != 1 || !isa<PointerType>(FTy->getParamType(0)))
+      return false;
+
+    Changed |= setDoesNotAccessMemory(F);
+    Changed |= setDoesNotThrow(F);
+    return Changed;
+
   default:
     // FIXME: It'd be really nice to cover all the library functions we're
     // aware of here.

diff --git a/llvm/test/Transforms/InferFunctionAttrs/annotate.ll b/llvm/test/Transforms/InferFunctionAttrs/annotate.ll
index 1cb7ab1..8ac45df 100644 (file)
--- a/llvm/test/Transforms/InferFunctionAttrs/annotate.ll
+++ b/llvm/test/Transforms/InferFunctionAttrs/annotate.ll
@@ -1,6 +1,7 @@
 ; RUN: opt < %s -inferattrs -S | FileCheck %s
 ; RUN: opt < %s -passes=inferattrs -S | FileCheck %s
 ; RUN: opt < %s -mtriple=x86_64-apple-macosx10.8.0 -inferattrs -S | FileCheck -check-prefix=CHECK-POSIX %s
+; RUN: opt < %s -mtriple=nvptx -inferattrs -S | FileCheck -check-prefix=CHECK-NVPTX %s
 
 declare i8* @fopen(i8*, i8*)
 ; CHECK: declare noalias i8* @fopen(i8* nocapture readonly, i8* nocapture readonly) [[G0:#[0-9]]] 
@@ -33,3 +34,7 @@ declare i32 @gettimeofday(i8*, i8*)
 ; CHECK: attributes [[G1]] = { nounwind readonly }
 ; CHECK-POSIX: attributes [[G0]] = { nounwind }
 ; CHECK-POSIX: attributes [[G2]] = { argmemonly }
+
+declare i32 @__nvvm_reflect(i8*)
+; CHECK-NVPTX: declare i32 @__nvvm_reflect(i8*) [[G0:#[0-9]+]]
+; CHECK-NVPTX: attributes [[G0]] = { nounwind readnone }