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authorRoland Scheidegger <[email protected]>2016-12-21 04:52:16 +0100
committerRoland Scheidegger <[email protected]>2017-01-05 23:59:38 +0100
commitdb7e786a2552d808e512ba33fbc9b19d8bb37108 (patch)
treedee13e7ebefbe6e98096a3a58a33c738267be9ef /src/gallium/auxiliary
parenta8eeb089c0e2e171ffaf8cba3cd0e5aea97b388f (diff)
llvmpipe: (trivial) minimally simplify mask construction
simd instruction sets usually have comparisons for equal, not unequal. So use a different comparison against the mask itself - which also means we don't need a all-zero as well as a all-one (for the pxor) reg. Also add code to avoid scalar expansion of i1 values which we definitely shouldn't do. There's problems with this though with llvm select interaction, so it's disabled (basically using llvm select instead of intrinsics may still produce atrocious code, even in cases where we figured it should not, albeit I think this could probably be fixed with some better selection of optimization passes, but I have zero idea there really). Reviewed-by: Jose Fonseca <[email protected]>
Diffstat (limited to 'src/gallium/auxiliary')
-rw-r--r--src/gallium/auxiliary/gallivm/lp_bld_logic.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_logic.c b/src/gallium/auxiliary/gallivm/lp_bld_logic.c
index 1a50e82c241..524917abe27 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_logic.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_logic.c
@@ -327,6 +327,8 @@ lp_build_select(struct lp_build_context *bld,
* supported yet for a long time, and LLVM will generate poor code when
* the mask is not the result of a comparison.
* Also, llvm 3.7 may miscompile them (bug 94972).
+ * XXX: Even if the instruction was an SExt, this may still produce
+ * terrible code. Try piglit stencil-twoside.
*/
/* Convert the mask to a vector of booleans.