Mesa (master): radv: emit fmuladd instead of fma to llvm.

[Dave Airlie]

Module: Mesa
Branch: master
Commit: 4e93d6baae2d00540b9bee0decff700d1aa6b247
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=4e93d6baae2d00540b9bee0decff700d1aa6b247

Author: Dave Airlie <airlied at redhat.com>
Date:   Wed Oct  4 03:06:04 2017 +0100

radv: emit fmuladd instead of fma to llvm.

For Vulkan SPIR-V the spec states
fma() Inherited from OpFMul followed by OpFAdd.

Matt says the backend will do the right thing depending on the
hardware being compiled for, if you use the fmuladd intrinsic.

Using the Mad Max pts test, on high settings at 4K:
CHP: 55->60
HGDD: 46->50
LM: 55->60
No change on Stronghold.

Thanks to Feral for spending the time to track this down.

Reviewed-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
Cc: "17.2" <mesa-stable at lists.freedesktop.org>
Signed-off-by: Dave Airlie <airlied at redhat.com>

---

 src/amd/common/ac_nir_to_llvm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/amd/common/ac_nir_to_llvm.c b/src/amd/common/ac_nir_to_llvm.c
index d7b6259fe8..11ba487f37 100644
--- a/src/amd/common/ac_nir_to_llvm.c
+++ b/src/amd/common/ac_nir_to_llvm.c
@@ -1707,7 +1707,7 @@ static void visit_alu(struct ac_nir_context *ctx, const nir_alu_instr *instr)
 						      result);
 		break;
 	case nir_op_ffma:
-		result = emit_intrin_3f_param(&ctx->ac, "llvm.fma",
+		result = emit_intrin_3f_param(&ctx->ac, "llvm.fmuladd",
 		                              ac_to_float_type(&ctx->ac, def_type), src[0], src[1], src[2]);
 		break;
 	case nir_op_ibitfield_extract: