[Mesa-dev] [PATCH] gallivm: force sse instructions for llvm 3.5+

[Maarten Lankhorst]

This fixes a crash when llvmpipe tries to use sse instructions,
but llvm detects a cpu that doesn't support them.

Fixes for example piglit/bin/amd_seamless_cubemap_per_texture -fbo -auto
on i386 when run inside "qemu -cpu qemu32", which would otherwise error with:
"LLVM ERROR: Do not know how to split the result of this operator!"

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at canonical.com>
---

diff --git a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
index 55aa8b9..f2f8906 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
+++ b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
@@ -479,10 +479,38 @@ lp_build_create_jit_compiler_for_module(LLVMExecutionEngineRef *OutJIT,
       if (util_cpu_caps.has_f16c) {
          MAttrs.push_back("+f16c");
       }
-      builder.setMAttrs(MAttrs);
    }
 
 #if HAVE_LLVM >= 0x0305
+   /*
+    * llvm 3.5 no longer supports cpuid based autodetect.
+    * This breaks on "qemu -cpu qemu32" which is detected as pentium2 by llvm's
+    * sys::getHostCPUName(), but does support sse2.
+    *
+    * For this reason force the use of sse extensions when available, so our
+    * understanding of the cpu is in sync with llvm's.
+    */
+
+   else if (util_cpu_caps.has_sse4_2)
+      MAttrs.push_back("+sse42");
+   else if (util_cpu_caps.has_sse4_1)
+      MAttrs.push_back("+sse41");
+   else if (util_cpu_caps.has_ssse3)
+      MAttrs.push_back("+ssse3");
+   else if (util_cpu_caps.has_sse3)
+      MAttrs.push_back("+sse3");
+   else if (util_cpu_caps.has_sse2)
+      MAttrs.push_back("+sse2");
+   else if (util_cpu_caps.has_sse)
+      MAttrs.push_back("+sse");
+   else if (util_cpu_caps.has_mmx)
+      MAttrs.push_back("+sse");
+
+   if (util_cpu_caps.has_3dnow_ext)
+      MAttrs.push_back("+3dnowa");
+   else if (util_cpu_caps.has_3dnow)
+      MAttrs.push_back("+3dnow");
+
    StringRef MCPU = llvm::sys::getHostCPUName();
    /*
     * The cpu bits are no longer set automatically, so need to set mcpu manually.
@@ -498,6 +526,7 @@ lp_build_create_jit_compiler_for_module(LLVMExecutionEngineRef *OutJIT,
     */
    builder.setMCPU(MCPU);
 #endif
+   builder.setMAttrs(MAttrs);
 
    ShaderMemoryManager *MM = new ShaderMemoryManager();
    *OutCode = MM->getGeneratedCode();