Mesa (master): gallivm: Use vector selects on LLVM 3.3+.

[Jose Fonseca]

Module: Mesa
Branch: master
Commit: cdf7c6b83dad7eb6a7600af61403315b02dcf13f
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=cdf7c6b83dad7eb6a7600af61403315b02dcf13f

Author: Jose Fonseca <jfonseca at vmware.com>
Date:   Thu Mar 31 23:37:34 2016 +0100

gallivm: Use vector selects on LLVM 3.3+.

This is an old patch I had around.

Vector selects seem to work well from LLVM 3.3.  Using them should
improve code quality, as it might make constant propagation pass more
effective.

Tested lp_test_*

Reviewed-by: Roland Scheidegger <sroland at vmware.com>

---

 src/gallium/auxiliary/gallivm/lp_bld_logic.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/gallium/auxiliary/gallivm/lp_bld_logic.c b/src/gallium/auxiliary/gallivm/lp_bld_logic.c
index 19d30d0..5b0b6c6 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_logic.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_logic.c
@@ -314,11 +314,13 @@ lp_build_select(struct lp_build_context *bld,
       mask = LLVMBuildTrunc(builder, mask, LLVMInt1TypeInContext(lc), "");
       res = LLVMBuildSelect(builder, mask, a, b, "");
    }
-   else if (0) {
+   else if (HAVE_LLVM >= 0x0303) {
       /* Generate a vector select.
        *
-       * XXX: Using vector selects would avoid emitting intrinsics, but they aren't
-       * properly supported yet.
+       * Using vector selects would avoid emitting intrinsics, but they weren't
+       * properly supported yet for a long time.
+       *
+       * LLVM 3.3 appears to reliably support it.
        *
        * LLVM 3.1 supports it, but it yields buggy code (e.g. lp_blend_test).
        *