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[NVPTX] Read __CUDA_FTZ from module flags in NVVMReflect. 

Summary:
Previously the NVVMReflect pass would read its configuration from
command-line flags or a static configuration given to the pass at
instantiation time.

This doesn't quite work for clang's use-case.  It needs to pass a value
for __CUDA_FTZ down on a per-module basis.  We use a module flag for
this, so the NVVMReflect pass needs to be updated to read said flag.

Reviewers: tra, rnk

Subscribers: cfe-commits, jholewinski

Differential Revision: http://reviews.llvm.org/D18672

llvm-svn: 265090
This commit is contained in:
Justin Lebar 2016-04-01 01:09:07 +00:00
parent 645c3014a1
commit efcc81cbb4
2 changed files with 30 additions and 7 deletions
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24
llvm/lib/Target/NVPTX/NVVMReflect.cpp
View File

@ -7,11 +7,16 @@
//
//===----------------------------------------------------------------------===//
//
// This pass replaces occurrences of __nvvm_reflect("string") and
// llvm.nvvm.reflect with an integer based on the value of -nvvm-reflect-list
// string=<int>.
// This pass replaces occurrences of __nvvm_reflect("foo") and llvm.nvvm.reflect
// with an integer.
//
// If we see a string not specified in our flags, we replace that call with 0.
// We choose the value we use by looking, in this order, at:
//
// * the -nvvm-reflect-list flag, which has the format "foo=1,bar=42",
// * the StringMap passed to the pass's constructor, and
// * metadata in the module itself.
//
// If we see an unknown string, we replace its call with 0.
//
//===----------------------------------------------------------------------===//
@ -55,10 +60,9 @@ public:
static char ID;
NVVMReflect() : NVVMReflect(StringMap<int>()) {}
NVVMReflect(const StringMap<int> &Mapping) : FunctionPass(ID) {
NVVMReflect(const StringMap<int> &Mapping)
: FunctionPass(ID), VarMap(Mapping) {
initializeNVVMReflectPass(*PassRegistry::getPassRegistry());
for (const auto &KV : Mapping)
VarMap[KV.getKey()] = KV.getValue();
setVarMap();
}
@ -206,6 +210,12 @@ bool NVVMReflect::runOnFunction(Function &F) {
auto Iter = VarMap.find(ReflectArg);
if (Iter != VarMap.end())
ReflectVal = Iter->second;
else if (ReflectArg == "__CUDA_FTZ") {
// Try to pull __CUDA_FTZ from the nvvm-reflect-ftz module flag.
if (auto *Flag = mdconst::extract_or_null<ConstantInt>(
F.getParent()->getModuleFlag("nvvm-reflect-ftz")))
ReflectVal = Flag->getSExtValue();
}
Call->replaceAllUsesWith(ConstantInt::get(Call->getType(), ReflectVal));
ToRemove.push_back(Call);
}

13
llvm/test/CodeGen/NVPTX/nvvm-reflect-module-flag.ll Normal file
View File

@ -0,0 +1,13 @@
; RUN: opt < %s -S -nvvm-reflect | FileCheck %s
declare i32 @__nvvm_reflect(i8*)
@str = private unnamed_addr addrspace(1) constant [11 x i8] c"__CUDA_FTZ\00"
define i32 @foo() {
%call = call i32 @__nvvm_reflect(i8* addrspacecast (i8 addrspace(1)* getelementptr inbounds ([11 x i8], [11 x i8] addrspace(1)* @str, i32 0, i32 0) to i8*))
; CHECK: ret i32 42
ret i32 %call
}
!llvm.module.flags = !{!0}
!0 = !{i32 4, !"nvvm-reflect-ftz", i32 42}