[Bug,92214] Flightgear crashes during splashboot with R600 driver, LLVM 3.7.0 and mesa 11.0.2
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Message ID bug-92214-502-joX2by0iF5@http.bugs.freedesktop.org/
State New
Headers show

Commit Message

bugzilla-daemon@freedesktop.org Oct. 14, 2015, 6:36 a.m. UTC
https://bugs.freedesktop.org/show_bug.cgi?id=92214

--- Comment #30 from Barto <mister.freeman@laposte.net> ---
I found the cause of this bug,

it's llvm 3.7.0, the llvm git commit who has introduced this bug is :

cd83d5b5071f072882ad06cc4b904b2d27d1e54a

https://github.com/llvm-mirror/llvm/commit/cd83d5b5071f072882ad06cc4b904b2d27d1e54a

the problem is that llvm 3.7.0 treats my pentium dual core as a "penryn",

penryn supports SSE4, but not the pentium dual core series ( CPU family 6 model
23 ),

the faulty commit has deleted a test about SSE4 :

return HasSSE41 ? "penryn" : "core2";

the solution is simply to add this test for CPU family 6 model 23, I created a
patch who solves this bug :

using
                // the 45 nm process.
         return "penryn";

this patch has been sent to llvm's bugzilla, I hope they will accept it

Patch
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--- a/lib/Support/Host.cpp    2015-10-14 07:13:52.381374679 +0200
+++ b/lib/Support/Host.cpp   2015-10-14 07:13:28.224708323 +0200
@@ -332,6 +332,8 @@ 
                // 17h. All processors are manufactured using the 45 nm
process.
                //
                // 45nm: Penryn , Wolfdale, Yorkfield (XE)
+        // Not all Penryn processors support SSE 4.1 (such as the Pentium
brand)
+        return HasSSE41 ? "penryn" : "core2";          
       case 29: // Intel Xeon processor MP. All processors are manufactured