[Mesa-dev] [PATCH] gallivm: use fallback code for mul_hi with llvm >= 7.0

[sroland at vmware.com]

From: Roland Scheidegger <sroland at vmware.com>

LLVM 7.0 ditched the pmulu intrinsics.
This is only a trivial patch to use the fallback code instead.
It'll likely produce atrocious code since the pattern doesn't match what
llvm itself uses in its autoupgrade paths, hence the pattern won't be
recognized.

Should fix https://bugs.freedesktop.org/show_bug.cgi?id=111496
---
 src/gallium/auxiliary/gallivm/lp_bld_arit.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/gallium/auxiliary/gallivm/lp_bld_arit.c b/src/gallium/auxiliary/gallivm/lp_bld_arit.c
index c4931c0b230..f1866c6625f 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_arit.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_arit.c
@@ -1169,8 +1169,13 @@ lp_build_mul_32_lohi_cpu(struct lp_build_context *bld,
     * https://llvm.org/bugs/show_bug.cgi?id=30845
     * So, whip up our own code, albeit only for length 4 and 8 (which
     * should be good enough)...
+    * FIXME: For llvm >= 7.0 we should match the autoupgrade pattern
+    * (bitcast/and/mul/shuffle for unsigned, bitcast/shl/ashr/mul/shuffle
+    * for signed), which the fallback code does not, without this llvm
+    * will likely still produce atrocious code.
     */
-   if ((bld->type.length == 4 || bld->type.length == 8) &&
+   if (HAVE_LLVM < 0x0700 &&
+       (bld->type.length == 4 || bld->type.length == 8) &&
        ((util_cpu_caps.has_sse2 && (bld->type.sign == 0)) ||
         util_cpu_caps.has_sse4_1)) {
       const char *intrinsic = NULL;
-- 
2.17.1