diff options
| author | Samuel Pitoiset <[email protected]> | 2020-03-25 18:17:06 +0100 |
|---|---|---|
| committer | Eric Engestrom <[email protected]> | 2020-03-30 12:26:45 +0200 |
| commit | f4179f1b17d2d6f5e5148e01f5094005299065b4 (patch) | |
| tree | f1536d0e7dabddcd7b4b4e3190d2818416070281 | |
| parent | cbc7ba2e473e56b5c02bf422f8a7d51945b0d693 (diff) | |
ac/nir: use llvm.amdgcn.rcp for nir_op_frcp
Instead of emitting 1.0 / x which includes a slow division that
LLVM doesn't always optimize even if the metadata is correctly set.
pipeline-db (VEG10/LLVM 9):
Totals from affected shaders:
SGPRS: 50384 -> 50312 (-0.14 %)
VGPRS: 42572 -> 42696 (0.29 %)
Spilled SGPRs: 1372 -> 1372 (0.00 %)
Code Size: 5692040 -> 5691428 (-0.01 %) bytes
Max Waves: 3954 -> 3951 (-0.08 %)
pipeline-db (VEG10/LLVM 10):
Totals from affected shaders:
SGPRS: 78512 -> 78464 (-0.06 %)
VGPRS: 62408 -> 62484 (0.12 %)
Spilled SGPRs: 1502 -> 1502 (0.00 %)
Code Size: 8106188 -> 8103372 (-0.03 %) bytes
Max Waves: 7759 -> 7753 (-0.08 %)
pipeline-db (VEGA10/LLVM 11 - 92744f62478):
Totals from affected shaders:
SGPRS: 112760 -> 113232 (0.42 %)
VGPRS: 111132 -> 110568 (-0.51 %)
Spilled SGPRs: 5870 -> 5940 (1.19 %)
Spilled VGPRs: 650 -> 652 (0.31 %)
Code Size: 11887232 -> 11561744 (-2.74 %) bytes
Max Waves: 8964 -> 9015 (0.57 %)
LLVM 11 (master) is more affected than previous versions, but
based on the small impact with LLVM 9/10, I decided to emit it
unconditionally.
Cc: 20.0 <[email protected]>
Signed-off-by: Samuel Pitoiset <[email protected]>
Reviewed-by: Bas Nieuwenhuizen <[email protected]>
Reviewed-by: Marek Olšák <[email protected]>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4326>
(cherry picked from commit 66426ce119b3b647f9ace62b74f18342cacd43a4)
| -rw-r--r-- | .pick_status.json | 2 | ||||
| -rw-r--r-- | src/amd/llvm/ac_nir_to_llvm.c | 4 |
2 files changed, 3 insertions, 3 deletions
diff --git a/.pick_status.json b/.pick_status.json index 2d1b2acaf62..dc03de49ae9 100644 --- a/.pick_status.json +++ b/.pick_status.json @@ -625,7 +625,7 @@ "description": "ac/nir: use llvm.amdgcn.rcp for nir_op_frcp", "nominated": true, "nomination_type": 0, - "resolution": 0, + "resolution": 1, "master_sha": null, "because_sha": null }, diff --git a/src/amd/llvm/ac_nir_to_llvm.c b/src/amd/llvm/ac_nir_to_llvm.c index f8f4d7e8206..f64399b5f77 100644 --- a/src/amd/llvm/ac_nir_to_llvm.c +++ b/src/amd/llvm/ac_nir_to_llvm.c @@ -688,8 +688,8 @@ static void visit_alu(struct ac_nir_context *ctx, const nir_alu_instr *instr) result = LLVMBuildFMul(ctx->ac.builder, src[0], src[1], ""); break; case nir_op_frcp: - src[0] = ac_to_float(&ctx->ac, src[0]); - result = ac_build_fdiv(&ctx->ac, LLVMConstReal(LLVMTypeOf(src[0]), 1.0), src[0]); + result = emit_intrin_1f_param(&ctx->ac, "llvm.amdgcn.rcp", + ac_to_float_type(&ctx->ac, def_type), src[0]); break; case nir_op_iand: result = LLVMBuildAnd(ctx->ac.builder, src[0], src[1], ""); |