Mesa (main): nir: create ffma from builders more often

[GitLab Mirror]

Module: Mesa
Branch: main
Commit: 174a4f36f9c4c6a9d180bbc5e9da1bfc92c97b4d
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=174a4f36f9c4c6a9d180bbc5e9da1bfc92c97b4d

Author: Rhys Perry <pendingchaos02 at gmail.com>
Date:   Thu Jul 23 11:40:11 2020 +0100

nir: create ffma from builders more often

We will not be able to combine instructions into ffma later if they are
exact, so create them from the start. They can be lowered later if they
are unwanted.

fossil-db (GFX10.3):
Totals from 16589 (11.34% of 146267) affected shaders:
VGPRs: 938872 -> 938704 (-0.02%)
SpillSGPRs: 11334 -> 10785 (-4.84%)
CodeSize: 96551964 -> 96498040 (-0.06%); split: -0.08%, +0.02%
MaxWaves: 338760 -> 338772 (+0.00%)
Instrs: 18356857 -> 18350486 (-0.03%); split: -0.06%, +0.02%
Latency: 561563310 -> 561414360 (-0.03%); split: -0.08%, +0.05%
InvThroughput: 145629673 -> 145594740 (-0.02%); split: -0.04%, +0.01%

fossil-db (GFX10):
Totals from 16252 (11.11% of 146267) affected shaders:
VGPRs: 893820 -> 893744 (-0.01%)
SpillSGPRs: 11334 -> 10785 (-4.84%)
CodeSize: 95890244 -> 95839124 (-0.05%); split: -0.08%, +0.02%
MaxWaves: 367704 -> 367734 (+0.01%)
Instrs: 18199741 -> 18194437 (-0.03%); split: -0.06%, +0.03%
Latency: 560912971 -> 560854179 (-0.01%); split: -0.07%, +0.06%
InvThroughput: 142899814 -> 142877939 (-0.02%); split: -0.03%, +0.02%

fossil-db (GFX9):
Totals from 16287 (11.12% of 146401) affected shaders:
SGPRs: 1312784 -> 1312768 (-0.00%); split: -0.05%, +0.05%
VGPRs: 931440 -> 931444 (+0.00%); split: -0.00%, +0.00%
SpillSGPRs: 14623 -> 14597 (-0.18%)
CodeSize: 94428788 -> 94344404 (-0.09%); split: -0.10%, +0.01%
MaxWaves: 90105 -> 90109 (+0.00%)
Instrs: 18486905 -> 18473434 (-0.07%); split: -0.08%, +0.01%
Latency: 720947295 -> 720818323 (-0.02%); split: -0.07%, +0.05%
InvThroughput: 365240104 -> 365224659 (-0.00%); split: -0.02%, +0.01%

Signed-off-by: Rhys Perry <pendingchaos02 at gmail.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig at collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8056>

---

 src/compiler/nir/nir_builtin_builder.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/src/compiler/nir/nir_builtin_builder.c b/src/compiler/nir/nir_builtin_builder.c
index 602d752582c..c8845f48325 100644
--- a/src/compiler/nir/nir_builtin_builder.c
+++ b/src/compiler/nir/nir_builtin_builder.c
@@ -33,10 +33,10 @@ nir_cross3(nir_builder *b, nir_ssa_def *x, nir_ssa_def *y)
    unsigned yzx[3] = { 1, 2, 0 };
    unsigned zxy[3] = { 2, 0, 1 };
 
-   return nir_fsub(b, nir_fmul(b, nir_swizzle(b, x, yzx, 3),
-                                  nir_swizzle(b, y, zxy, 3)),
-                      nir_fmul(b, nir_swizzle(b, x, zxy, 3),
-                                  nir_swizzle(b, y, yzx, 3)));
+   return nir_ffma(b, nir_swizzle(b, x, yzx, 3),
+                      nir_swizzle(b, y, zxy, 3),
+                      nir_fneg(b, nir_fmul(b, nir_swizzle(b, x, zxy, 3),
+                                              nir_swizzle(b, y, yzx, 3))));
 }
 
 nir_ssa_def*
@@ -149,7 +149,7 @@ nir_smoothstep(nir_builder *b, nir_ssa_def *edge0, nir_ssa_def *edge1, nir_ssa_d
                               nir_fsub(b, edge1, edge0)));
 
    /* result = t * t * (3 - 2 * t) */
-   return nir_fmul(b, t, nir_fmul(b, t, nir_fsub(b, f3, nir_fmul(b, f2, t))));
+   return nir_fmul(b, t, nir_fmul(b, t, nir_a_minus_bc(b, f3, f2, t)));
 }
 
 nir_ssa_def*
@@ -226,9 +226,9 @@ nir_atan(nir_builder *b, nir_ssa_def *y_over_x)
       build_fsum(b, polynomial_terms, ARRAY_SIZE(polynomial_terms));
 
    /* range-reduction fixup */
-   tmp = nir_fadd(b,
-                  nir_fmul(b, nir_b2f(b, nir_flt(b, one, abs_y_over_x), bit_size),
-                           nir_fadd_imm(b, nir_fmul_imm(b, tmp, -2.0f), M_PI_2)),
+   tmp = nir_ffma(b,
+                  nir_b2f(b, nir_flt(b, one, abs_y_over_x), bit_size),
+                  nir_ffma_imm12(b, tmp, -2.0f, M_PI_2),
                   tmp);
 
    /* sign fixup */
@@ -303,8 +303,7 @@ nir_atan2(nir_builder *b, nir_ssa_def *y, nir_ssa_def *x)
     * coordinate system.
     */
    nir_ssa_def *arc =
-      nir_fadd(b, nir_fmul_imm(b, nir_b2f(b, flip, bit_size), M_PI_2),
-                  nir_atan(b, tan));
+      nir_ffma_imm1(b, nir_b2f(b, flip, bit_size), M_PI_2, nir_atan(b, tan));
 
    /* Rather convoluted calculation of the sign of the result.  When x < 0 we
     * cannot use fsign because we need to be able to distinguish between