From cad60420d5ea36a4b6fa2e6c91317f71423aa63e Mon Sep 17 00:00:00 2001 From: Roland Scheidegger Date: Thu, 19 Jun 2014 03:27:26 +0200 Subject: [PATCH] gallivm: set mcpu when initializing llvm execution engine Previously llvm detected cpu features automatically when the execution engine was created (based on host cpu). This is no longer the case, which meant llvm was then not able to emit some of the intrinsics we used as we didn't specify any sse attributes (only on avx supporting systems this was not a problem since despite at least some llvm versions enabling it anyway we always set this manually). So, instead of trying to figure out which MAttrs to set just set MCPU. This fixes https://bugs.freedesktop.org/show_bug.cgi?id=77493. Reviewed-by: Jose Fonseca Tested-by: Vinson Lee --- src/gallium/auxiliary/gallivm/lp_bld_misc.cpp | 22 +++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp index 38fbe1fc7e5..6bea9648922 100644 --- a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp +++ b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp @@ -468,8 +468,8 @@ lp_build_create_jit_compiler_for_module(LLVMExecutionEngineRef *OutJIT, /* * AVX feature is not automatically detected from CPUID by the X86 target * yet, because the old (yet default) JIT engine is not capable of - * emitting the opcodes. But as we're using MCJIT here, it is safe to - * add set this attribute. + * emitting the opcodes. On newer llvm versions it is and at least some + * versions (tested with 3.3) will emit avx opcodes without this anyway. */ MAttrs.push_back("+avx"); if (util_cpu_caps.has_f16c) { @@ -478,12 +478,30 @@ lp_build_create_jit_compiler_for_module(LLVMExecutionEngineRef *OutJIT, builder.setMAttrs(MAttrs); } +#if HAVE_LLVM >= 0x0305 + StringRef MCPU = llvm::sys::getHostCPUName(); + /* + * The cpu bits are no longer set automatically, so need to set mcpu manually. + * Note that the MAttrs set above will be sort of ignored (since we should + * not set any which would not be set by specifying the cpu anyway). + * It ought to be safe though since getHostCPUName() should include bits + * not only from the cpu but environment as well (for instance if it's safe + * to use avx instructions which need OS support). According to + * http://llvm.org/bugs/show_bug.cgi?id=19429 however if I understand this + * right it may be necessary to specify older cpu (or disable mattrs) though + * when not using MCJIT so no instructions are generated which the old JIT + * can't handle. Not entirely sure if we really need to do anything yet. + */ + builder.setMCPU(MCPU); +#endif + ShaderMemoryManager *MM = new ShaderMemoryManager(); *OutCode = MM->getGeneratedCode(); builder.setJITMemoryManager(MM); ExecutionEngine *JIT; + #if HAVE_LLVM >= 0x0302 JIT = builder.create(); #else -- 2.30.2