[Mesa-dev] [PATCH] ac: use llvm.amdgcn.fract intrinsic for nir_op_ffract

[Samuel Pitoiset]

Noticed with a Doom shader.

29077 shaders in 15096 tests
Totals:
SGPRS: 1282125 -> 1282133 (0.00 %)
VGPRS: 908716 -> 908616 (-0.01 %)
Spilled SGPRs: 24811 -> 24779 (-0.13 %)
Code Size: 49048176 -> 48936488 (-0.23 %) bytes
Max Waves: 244232 -> 244226 (-0.00 %)

Totals from affected shaders:
SGPRS: 229584 -> 229592 (0.00 %)
VGPRS: 163268 -> 163168 (-0.06 %)
Spilled SGPRs: 8682 -> 8650 (-0.37 %)
Code Size: 12819572 -> 12707884 (-0.87 %) bytes
Max Waves: 24398 -> 24392 (-0.02 %)

Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
---
 src/amd/common/ac_llvm_build.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/src/amd/common/ac_llvm_build.c b/src/amd/common/ac_llvm_build.c
index 0cab4d4a9b5..9cf1c6f8792 100644
--- a/src/amd/common/ac_llvm_build.c
+++ b/src/amd/common/ac_llvm_build.c
@@ -2155,19 +2155,18 @@ LLVMValueRef ac_build_fract(struct ac_llvm_context *ctx, LLVMValueRef src0,
 	char *intr;
 
 	if (bitsize == 32) {
-		intr = "llvm.floor.f32";
+		intr = "llvm.amdgcn.fract.f32";
 		type = ctx->f32;
 	} else {
-		intr = "llvm.floor.f64";
+		intr = "llvm.amdgcn.fract.f64";
 		type = ctx->f64;
 	}
 
 	LLVMValueRef params[] = {
 		src0,
 	};
-	LLVMValueRef floor = ac_build_intrinsic(ctx, intr, type, params, 1,
-						AC_FUNC_ATTR_READNONE);
-	return LLVMBuildFSub(ctx->builder, src0, floor, "");
+	return ac_build_intrinsic(ctx, intr, type, params, 1,
+				  AC_FUNC_ATTR_READNONE);
 }
 
 LLVMValueRef ac_build_isign(struct ac_llvm_context *ctx, LLVMValueRef src0,
-- 
2.21.0