From: Marek Olšák <marek.ol...@amd.com>
Cc: 18.1 18.2 <mesa-sta...@lists.freedesktop.org>
---
src/amd/common/ac_llvm_build.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/src/amd/common/ac_llvm_build.c b/src/amd/common/ac_llvm_build.c
index c741a1ab62d..629cd2a7527 100644
--- a/src/amd/common/ac_llvm_build.c
+++ b/src/amd/common/ac_llvm_build.c
@@ -554,21 +554,28 @@ LLVMValueRef ac_build_expand_to_vec4(struct
ac_llvm_context *ctx,
chan[num_channels++] = LLVMGetUndef(elemtype);
return ac_build_gather_values(ctx, chan, 4);
}
LLVMValueRef
ac_build_fdiv(struct ac_llvm_context *ctx,
LLVMValueRef num,
LLVMValueRef den)
{
- LLVMValueRef ret = LLVMBuildFDiv(ctx->builder, num, den, "");
+ /* If we do (num / den), LLVM >= 7.0 does:
+ * return num * v_rcp_f32(den * (fabs(den) > 0x1.0p+96f ? 0x1.0p-32f
: 1.0f));
+ *
+ * If we do (num * (1 / den)), LLVM does:
+ * return num * v_rcp_f32(den);
+ */
+ LLVMValueRef rcp = LLVMBuildFDiv(ctx->builder, ctx->f32_1, den, "");
+ LLVMValueRef ret = LLVMBuildFMul(ctx->builder, num, rcp, "");
/* Use v_rcp_f32 instead of precise division. */
if (!LLVMIsConstant(ret))
LLVMSetMetadata(ret, ctx->fpmath_md_kind,
ctx->fpmath_md_2p5_ulp);
return ret;
}
/* Coordinates for cube map selection. sc, tc, and ma are as in Table 8.27
* of the OpenGL 4.5 (Compatibility Profile) specification, except ma is
* already multiplied by two. id is the cube face number.
--
2.17.1
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