On 04/16/2019 06:35 PM, srol...@vmware.com wrote:
From: Roland Scheidegger <srol...@vmware.com>
llvm 8 removed saturated unsigned add / sub x86 sse2 intrinsics, and
now llvm 9 removed the signed versions as well - they were proposed for
removal earlier, but the pattern to recognize those was very complex,
so it wasn't done then. However, instead of these arch-specific
intrinsics, there's now arch-independent intrinsics for saturated
add / sub, both for signed and unsigned, so use these.
They should have only advantages (work with arbitrary vector sizes,
optimal code for all archs), although I don't know how well they work
in practice for other archs (at least for x86 they do the right thing).
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110454
---
src/gallium/auxiliary/gallivm/lp_bld_arit.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_arit.c
b/src/gallium/auxiliary/gallivm/lp_bld_arit.c
index 057c50ed278..02fb81afe51 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_arit.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_arit.c
@@ -555,6 +555,12 @@ lp_build_add(struct lp_build_context *bld,
return bld->one;
if (!type.floating && !type.fixed) {
+ if (HAVE_LLVM >= 0x0900) {
+ char intrin[32];
+ intrinsic = type.sign ? "llvm.sadd.sat" : "llvm.uadd.sat";
+ lp_format_intrinsic(intrin, sizeof intrin, intrinsic,
bld->vec_type);
+ return lp_build_intrinsic_binary(builder, intrin, bld->vec_type,
a, b);
+ }
if (type.width * type.length == 128) {
if (util_cpu_caps.has_sse2) {
if (type.width == 8)
@@ -625,6 +631,7 @@ lp_build_add(struct lp_build_context *bld,
* NOTE: cmp/select does sext/trunc of the mask. Does not seem to
* interfere with llvm's ability to recognize the pattern but seems
* a bit brittle.
+ * NOTE: llvm 9+ always uses (non arch specific) intrinsic.
*/
LLVMValueRef overflowed = lp_build_cmp(bld, PIPE_FUNC_GREATER, a,
res);
res = lp_build_select(bld, overflowed,
@@ -876,6 +883,12 @@ lp_build_sub(struct lp_build_context *bld,
return bld->zero;
if (!type.floating && !type.fixed) {
+ if (HAVE_LLVM >= 0x0900) {
+ char intrin[32];
+ intrinsic = type.sign ? "llvm.ssub.sat" : "llvm.usub.sat";
+ lp_format_intrinsic(intrin, sizeof intrin, intrinsic,
bld->vec_type);
+ return lp_build_intrinsic_binary(builder, intrin, bld->vec_type,
a, b);
+ }
if (type.width * type.length == 128) {
if (util_cpu_caps.has_sse2) {
if (type.width == 8)
@@ -925,6 +938,7 @@ lp_build_sub(struct lp_build_context *bld,
* NOTE: cmp/select does sext/trunc of the mask. Does not seem to
* interfere with llvm's ability to recognize the pattern but seems
* a bit brittle.
+ * NOTE: llvm 9+ always uses (non arch specific) intrinsic.
*/
LLVMValueRef no_ov = lp_build_cmp(bld, PIPE_FUNC_GREATER, a, b);
a = lp_build_select(bld, no_ov, a, b);
LGTM.
Reviewed-by: Brian Paul <bri...@vmware.com>
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/mesa-dev
