Mesa (master): nir/alu_to_scalar: Use ssa_for_alu_src in hand-rolled expansions

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Module: Mesa
Branch: master
Commit: dd553bc67f8ab1513fd196b6ffb7c4a76723adfd
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=dd553bc67f8ab1513fd196b6ffb7c4a76723adfd

Author: Jason Ekstrand <jason.ekstrand at intel.com>
Date:   Wed Oct  3 12:14:20 2018 -0500

nir/alu_to_scalar: Use ssa_for_alu_src in hand-rolled expansions

The ssa_for_alu_src helper will correctly handle swizzles and other
source modifiers for you.  The expansions for unpack_half_2x16,
pack_uvec2_to_uint, and pack_uvec4_to_uint were all broken with regards
to swizzles.  The brokenness of unpack_half_2x16 was causing rendering
errors in Rise of the Tomb Raider on Intel ever since c11833ab24dcba26
which added an extra copy propagation to the optimization pipeline and
caused us to start seeing swizzles where we hadn't seen any before.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107926
Fixes: 9ce901058f3d "nir: Add lowering of nir_op_unpack_half_2x16."
Fixes: 9b8786eba955 "nir: Add lowering support for packing opcodes."
Tested-by: Alex Smith <asmith at feralinteractive.com>
Tested-by: Józef Kucia <joseph.kucia at gmail.com>
Reviewed-by: Matt Turner <mattst88 at gmail.com>

---

 src/compiler/nir/nir_lower_alu_to_scalar.c | 33 ++++++++++++++++--------------
 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/src/compiler/nir/nir_lower_alu_to_scalar.c b/src/compiler/nir/nir_lower_alu_to_scalar.c
index 742c8d8ee6..0be3aba945 100644
--- a/src/compiler/nir/nir_lower_alu_to_scalar.c
+++ b/src/compiler/nir/nir_lower_alu_to_scalar.c
@@ -107,11 +107,11 @@ lower_alu_instr_scalar(nir_alu_instr *instr, nir_builder *b)
       if (!b->shader->options->lower_pack_half_2x16)
          return false;
 
+      nir_ssa_def *src_vec2 = nir_ssa_for_alu_src(b, instr, 0);
+
       nir_ssa_def *val =
-         nir_pack_half_2x16_split(b, nir_channel(b, instr->src[0].src.ssa,
-                                                 instr->src[0].swizzle[0]),
-                                     nir_channel(b, instr->src[0].src.ssa,
-                                                 instr->src[0].swizzle[1]));
+         nir_pack_half_2x16_split(b, nir_channel(b, src_vec2, 0),
+                                     nir_channel(b, src_vec2, 1));
 
       nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(val));
       nir_instr_remove(&instr->instr);
@@ -130,9 +130,11 @@ lower_alu_instr_scalar(nir_alu_instr *instr, nir_builder *b)
       if (!b->shader->options->lower_unpack_half_2x16)
          return false;
 
+      nir_ssa_def *packed = nir_ssa_for_alu_src(b, instr, 0);
+
       nir_ssa_def *comps[2];
-      comps[0] = nir_unpack_half_2x16_split_x(b, instr->src[0].src.ssa);
-      comps[1] = nir_unpack_half_2x16_split_y(b, instr->src[0].src.ssa);
+      comps[0] = nir_unpack_half_2x16_split_x(b, packed);
+      comps[1] = nir_unpack_half_2x16_split_y(b, packed);
       nir_ssa_def *vec = nir_vec(b, comps, 2);
 
       nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa, nir_src_for_ssa(vec));
@@ -144,8 +146,8 @@ lower_alu_instr_scalar(nir_alu_instr *instr, nir_builder *b)
       assert(b->shader->options->lower_pack_snorm_2x16 ||
              b->shader->options->lower_pack_unorm_2x16);
 
-      nir_ssa_def *word =
-         nir_extract_u16(b, instr->src[0].src.ssa, nir_imm_int(b, 0));
+      nir_ssa_def *word = nir_extract_u16(b, nir_ssa_for_alu_src(b, instr, 0),
+                                             nir_imm_int(b, 0));
       nir_ssa_def *val =
          nir_ior(b, nir_ishl(b, nir_channel(b, word, 1), nir_imm_int(b, 16)),
                                 nir_channel(b, word, 0));
@@ -159,8 +161,8 @@ lower_alu_instr_scalar(nir_alu_instr *instr, nir_builder *b)
       assert(b->shader->options->lower_pack_snorm_4x8 ||
              b->shader->options->lower_pack_unorm_4x8);
 
-      nir_ssa_def *byte =
-         nir_extract_u8(b, instr->src[0].src.ssa, nir_imm_int(b, 0));
+      nir_ssa_def *byte = nir_extract_u8(b, nir_ssa_for_alu_src(b, instr, 0),
+                                            nir_imm_int(b, 0));
       nir_ssa_def *val =
          nir_ior(b, nir_ior(b, nir_ishl(b, nir_channel(b, byte, 3), nir_imm_int(b, 24)),
                                nir_ishl(b, nir_channel(b, byte, 2), nir_imm_int(b, 16))),
@@ -173,14 +175,15 @@ lower_alu_instr_scalar(nir_alu_instr *instr, nir_builder *b)
    }
 
    case nir_op_fdph: {
+      nir_ssa_def *src0_vec = nir_ssa_for_alu_src(b, instr, 0);
+      nir_ssa_def *src1_vec = nir_ssa_for_alu_src(b, instr, 1);
+
       nir_ssa_def *sum[4];
       for (unsigned i = 0; i < 3; i++) {
-         sum[i] = nir_fmul(b, nir_channel(b, instr->src[0].src.ssa,
-                                          instr->src[0].swizzle[i]),
-                              nir_channel(b, instr->src[1].src.ssa,
-                                          instr->src[1].swizzle[i]));
+         sum[i] = nir_fmul(b, nir_channel(b, src0_vec, i),
+                              nir_channel(b, src1_vec, i));
       }
-      sum[3] = nir_channel(b, instr->src[1].src.ssa, instr->src[1].swizzle[3]);
+      sum[3] = nir_channel(b, src1_vec, 3);
 
       nir_ssa_def *val = nir_fadd(b, nir_fadd(b, sum[0], sum[1]),
                                      nir_fadd(b, sum[2], sum[3]));