From e3d2ebac115f7b7899664fefc2652fb829acfa27 Mon Sep 17 00:00:00 2001 From: José Fonseca Date: Thu, 22 Jul 2010 18:37:46 +0100 Subject: llvmpipe: Avoid corrupting the FPU stack with MMX instructions on 32bit OSes. Unfortunately LLVM doesn't emit EMMS itself, and there is no easy/effective way to disable MMX. http://llvm.org/bugs/show_bug.cgi?id=3287 --- src/gallium/auxiliary/gallivm/lp_bld_misc.cpp | 24 ++++++++++++++++++++++++ src/gallium/drivers/llvmpipe/lp_state_fs.c | 5 +++++ 2 files changed, 29 insertions(+) diff --git a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp index 5a9488b5f79..072408b2689 100644 --- a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp +++ b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp @@ -39,6 +39,7 @@ #include #include #include +#include #include "pipe/p_config.h" #include "util/u_debug.h" @@ -141,4 +142,27 @@ lp_set_target_options(void) #if 0 llvm::UnsafeFPMath = true; #endif + +#if 0 + /* + * LLVM will generate MMX instructions for vectors <= 64 bits, leading to + * innefficient code, and in 32bit systems, to the corruption of the FPU + * stack given that it expects the user to generate the EMMS instructions. + * + * See also: + * - http://llvm.org/bugs/show_bug.cgi?id=3287 + * - http://l4.me.uk/post/2009/06/07/llvm-wrinkle-3-configuration-what-configuration/ + * + * XXX: Unfortunately this is not working. + */ + static boolean first = FALSE; + if (first) { + static const char* options[] = { + "prog", + "-disable-mmx" + }; + llvm::cl::ParseCommandLineOptions(2, const_cast(options)); + first = FALSE; + } +#endif } diff --git a/src/gallium/drivers/llvmpipe/lp_state_fs.c b/src/gallium/drivers/llvmpipe/lp_state_fs.c index 5953d690a41..dbcc286417a 100644 --- a/src/gallium/drivers/llvmpipe/lp_state_fs.c +++ b/src/gallium/drivers/llvmpipe/lp_state_fs.c @@ -676,6 +676,11 @@ generate_fragment(struct llvmpipe_context *lp, color_ptr); } +#ifdef PIPE_ARCH_X86 + /* Avoid corrupting the FPU stack on 32bit OSes. */ + lp_build_intrinsic(builder, "llvm.x86.mmx.emms", LLVMVoidType(), NULL, 0); +#endif + LLVMBuildRetVoid(builder); LLVMDisposeBuilder(builder); -- cgit v1.2.3