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[CUDA] Make PTXAS optimisation default to -O3 #5188

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Merged
merged 1 commit into from
Jan 30, 2022
Merged

[CUDA] Make PTXAS optimisation default to -O3 #5188

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9 changes: 3 additions & 6 deletions clang/lib/Driver/ToolChains/Cuda.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -422,9 +422,6 @@ void NVPTX::Assembler::ConstructJob(Compilation &C, const JobAction &JA,
CmdArgs.push_back("--return-at-end");
} else if (Arg *A = Args.getLastArg(options::OPT_O_Group)) {
// Map the -O we received to -O{0,1,2,3}.
//
// TODO: Perhaps we should map host -O2 to ptxas -O3. -O3 is ptxas's
// default, so it may correspond more closely to the spirit of clang -O2.

// -O3 seems like the least-bad option when -Osomething is specified to
// clang but it isn't handled below.
Expand All @@ -446,9 +443,9 @@ void NVPTX::Assembler::ConstructJob(Compilation &C, const JobAction &JA,
}
CmdArgs.push_back(Args.MakeArgString(llvm::Twine("-O") + OOpt));
} else {
// If no -O was passed, pass -O0 to ptxas -- no opt flag should correspond
// to no optimizations, but ptxas's default is -O3.
CmdArgs.push_back("-O0");
// If no -O was passed, pass -O3 to ptxas -- this makes ptxas's
// optimization level the same as the ptxjitcompiler.
CmdArgs.push_back("-O3");
}
if (DIKind == DebugDirectivesOnly)
CmdArgs.push_back("-lineinfo");
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6 changes: 3 additions & 3 deletions clang/test/Driver/cuda-external-tools.cu
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Expand Up @@ -40,10 +40,10 @@
// RUN: --no-cuda-noopt-device-debug -O2 -c %s 2>&1 \
// RUN: | FileCheck -check-prefixes=CHECK,ARCH64,SM35,OPT2 %s

// Regular compile without -O. This should result in us passing -O0 to ptxas.
// Regular compile without -O. This should result in us passing -O3 to ptxas.
// RUN: %clang -### -target x86_64-linux-gnu -c %s 2>&1 \
// RUN: --offload-arch=sm_35 --cuda-path=%S/Inputs/CUDA/usr/local/cuda \
// RUN: | FileCheck -check-prefixes=CHECK,ARCH64,SM35,OPT0 %s
// RUN: | FileCheck -check-prefixes=CHECK,ARCH64,SM35,OPT3 %s

// Regular compiles with -Os and -Oz. For lack of a better option, we map
// these to ptxas -O3.
Expand Down Expand Up @@ -75,7 +75,7 @@
// Compile with -fintegrated-as. This should still cause us to invoke ptxas.
// RUN: %clang -### -target x86_64-linux-gnu -fintegrated-as -c %s 2>&1 \
// RUN: --offload-arch=sm_35 --cuda-path=%S/Inputs/CUDA/usr/local/cuda \
// RUN: | FileCheck -check-prefixes=CHECK,ARCH64,SM35,OPT0 %s
// RUN: | FileCheck -check-prefixes=CHECK,ARCH64,SM35,OPT3 %s
// Check that we still pass -c when generating relocatable device code.
// RUN: %clang -### -target x86_64-linux-gnu -fintegrated-as -fgpu-rdc -c %s 2>&1 \
// RUN: --offload-arch=sm_35 --cuda-path=%S/Inputs/CUDA/usr/local/cuda \
Expand Down