[Mesa-dev] [PATCH 39/59] i965/fs: fix compares for doubles

[Samuel Iglesias Gonsálvez]

From: Connor Abbott <connor.w.abbott at intel.com>

The destination has to have the same source as the type, or else the
simulator will complain. As a result, we need to emit a CMP that
outputs a 64-bit wide result and then do a strided MOV to pick out the
low 32 bits of each channel.
---
 src/mesa/drivers/dri/i965/brw_fs_nir.cpp | 34 +++++++++++++++++++++++++++++---
 1 file changed, 31 insertions(+), 3 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
index 0ce25a0..70ffc6d 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
@@ -891,23 +891,51 @@ fs_visitor::nir_emit_alu(const fs_builder &bld, nir_alu_instr *instr)
    }
 
    case nir_op_flt:
+   case nir_op_fge:
+   case nir_op_feq:
+   case nir_op_fne: {
+      fs_reg dest = result;
+      if (nir_src_bit_size(instr->src[0].src) > 32) {
+         dest = bld.vgrf(BRW_REGISTER_TYPE_DF, 1);
+      }
+      brw_conditional_mod cond;
+      switch (instr->op) {
+      case nir_op_flt:
+         cond = BRW_CONDITIONAL_L;
+         break;
+      case nir_op_fge:
+         cond = BRW_CONDITIONAL_GE;
+         break;
+      case nir_op_feq:
+         cond = BRW_CONDITIONAL_Z;
+         break;
+      case nir_op_fne:
+         cond = BRW_CONDITIONAL_NZ;
+         break;
+      default:
+         unreachable("bad opcode");
+      }
+      bld.CMP(dest, op[0], op[1], cond);
+      if (nir_src_bit_size(instr->src[0].src) > 32) {
+         bld.MOV(result, stride(retype(dest, BRW_REGISTER_TYPE_UD), 2));
+      }
+      break;
+   }
+
    case nir_op_ilt:
    case nir_op_ult:
       bld.CMP(result, op[0], op[1], BRW_CONDITIONAL_L);
       break;
 
-   case nir_op_fge:
    case nir_op_ige:
    case nir_op_uge:
       bld.CMP(result, op[0], op[1], BRW_CONDITIONAL_GE);
       break;
 
-   case nir_op_feq:
    case nir_op_ieq:
       bld.CMP(result, op[0], op[1], BRW_CONDITIONAL_Z);
       break;
 
-   case nir_op_fne:
    case nir_op_ine:
       bld.CMP(result, op[0], op[1], BRW_CONDITIONAL_NZ);
       break;
-- 
2.5.0