[Mesa-dev] [PATCH] i965/nir: Resolve source modifiers on Gen8+ logic operations.

[Kenneth Graunke]

On Gen8+, AND/OR/XOR/NOT don't support the abs() source modifier, and
negate changes meaning to bitwise-not (~, not -).  This isn't what NIR
expects, so we should resolve the source modifers via a MOV.

+30 Piglits (fs-op-bit{and,or,xor}-not-abs-*).

Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
 src/mesa/drivers/dri/i965/brw_fs.cpp     | 11 +++++++++++
 src/mesa/drivers/dri/i965/brw_fs.h       |  1 +
 src/mesa/drivers/dri/i965/brw_fs_nir.cpp | 15 +++++++++++++++
 3 files changed, 27 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index d6acc23..428234f 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -1561,6 +1561,17 @@ fs_visitor::emit_sampleid_setup()
    return reg;
 }
 
+void
+fs_visitor::resolve_source_modifiers(fs_reg *src)
+{
+   if (!src->abs && !src->negate)
+      return;
+
+   fs_reg temp = retype(vgrf(1), src->type);
+   emit(MOV(temp, *src));
+   *src = temp;
+}
+
 fs_reg
 fs_visitor::fix_math_operand(fs_reg src)
 {
diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
index 70098d8..ec77962 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -299,6 +299,7 @@ public:
                      int texunit);
    fs_reg emit_mcs_fetch(fs_reg coordinate, int components, fs_reg sampler);
    void emit_gen6_gather_wa(uint8_t wa, fs_reg dst);
+   void resolve_source_modifiers(fs_reg *src);
    fs_reg fix_math_operand(fs_reg src);
    fs_inst *emit_math(enum opcode op, fs_reg dst, fs_reg src0);
    fs_inst *emit_math(enum opcode op, fs_reg dst, fs_reg src0, fs_reg src1);
diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
index 66f7918..a0300aa 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
@@ -935,15 +935,30 @@ fs_visitor::nir_emit_alu(nir_alu_instr *instr)
       break;
 
    case nir_op_inot:
+      if (brw->gen >= 8) {
+         resolve_source_modifiers(&op[0]);
+      }
       emit(NOT(result, op[0]));
       break;
    case nir_op_ixor:
+      if (brw->gen >= 8) {
+         resolve_source_modifiers(&op[0]);
+         resolve_source_modifiers(&op[1]);
+      }
       emit(XOR(result, op[0], op[1]));
       break;
    case nir_op_ior:
+      if (brw->gen >= 8) {
+         resolve_source_modifiers(&op[0]);
+         resolve_source_modifiers(&op[1]);
+      }
       emit(OR(result, op[0], op[1]));
       break;
    case nir_op_iand:
+      if (brw->gen >= 8) {
+         resolve_source_modifiers(&op[0]);
+         resolve_source_modifiers(&op[1]);
+      }
       emit(AND(result, op[0], op[1]));
       break;
 
-- 
2.2.2