Mesa (main): intel/compiler: INT DIV function does not support source modifiers

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Module: Mesa
Branch: main
Commit: e0533ebf16edcb8b9f0687d3155417e6c1c53d35
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=e0533ebf16edcb8b9f0687d3155417e6c1c53d35

Author: Marcin Ślusarz <marcin.slusarz at intel.com>
Date:   Tue Aug 24 10:50:42 2021 +0200

intel/compiler: INT DIV function does not support source modifiers

BSpec says that for all generations.

Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/5281
CC: mesa-stable

Signed-off-by: Marcin Ślusarz <marcin.slusarz at intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Reviewed-by: Sagar Ghuge <sagar.ghuge at intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12518>

---

 src/intel/compiler/brw_eu_emit.c     |  7 +++++++
 src/intel/compiler/brw_eu_validate.c | 23 +++++++++++++++++++++++
 src/intel/compiler/brw_shader.cpp    |  2 ++
 3 files changed, 32 insertions(+)

diff --git a/src/intel/compiler/brw_eu_emit.c b/src/intel/compiler/brw_eu_emit.c
index 2108cf6b8d7..ad276e60e60 100644
--- a/src/intel/compiler/brw_eu_emit.c
+++ b/src/intel/compiler/brw_eu_emit.c
@@ -2104,6 +2104,13 @@ void gfx6_math(struct brw_codegen *p,
       assert(src1.type != BRW_REGISTER_TYPE_F);
       assert(src1.file == BRW_GENERAL_REGISTER_FILE ||
              (devinfo->ver >= 8 && src1.file == BRW_IMMEDIATE_VALUE));
+      /* From BSpec 6647/47428 "[Instruction] Extended Math Function":
+       *     INT DIV function does not support source modifiers.
+       */
+      assert(!src0.negate);
+      assert(!src0.abs);
+      assert(!src1.negate);
+      assert(!src1.abs);
    } else {
       assert(src0.type == BRW_REGISTER_TYPE_F ||
              (src0.type == BRW_REGISTER_TYPE_HF && devinfo->ver >= 9));
diff --git a/src/intel/compiler/brw_eu_validate.c b/src/intel/compiler/brw_eu_validate.c
index 0e4ab19bf5c..68d41e3e661 100644
--- a/src/intel/compiler/brw_eu_validate.c
+++ b/src/intel/compiler/brw_eu_validate.c
@@ -2025,6 +2025,29 @@ instruction_restrictions(const struct intel_device_info *devinfo,
       }
    }
 
+   if (brw_inst_opcode(devinfo, inst) == BRW_OPCODE_MATH) {
+      unsigned math_function = brw_inst_math_function(devinfo, inst);
+      switch (math_function) {
+      case BRW_MATH_FUNCTION_INT_DIV_QUOTIENT_AND_REMAINDER:
+      case BRW_MATH_FUNCTION_INT_DIV_QUOTIENT:
+      case BRW_MATH_FUNCTION_INT_DIV_REMAINDER: {
+         /* Page 442 of the Broadwell PRM Volume 2a "Extended Math Function" says:
+          *    INT DIV function does not support source modifiers.
+          * Bspec 6647 extends it back to Ivy Bridge.
+          */
+         bool src0_valid = !brw_inst_src0_negate(devinfo, inst) &&
+                           !brw_inst_src0_abs(devinfo, inst);
+         bool src1_valid = !brw_inst_src1_negate(devinfo, inst) &&
+                           !brw_inst_src1_abs(devinfo, inst);
+         ERROR_IF(!src0_valid || !src1_valid,
+                  "INT DIV function does not support source modifiers.");
+         break;
+      }
+      default:
+         break;
+      }
+   }
+
    if (brw_inst_opcode(devinfo, inst) == BRW_OPCODE_DP4A) {
       /* Page 396 (page 412 of the PDF) of the DG1 PRM volume 2a says:
        *
diff --git a/src/intel/compiler/brw_shader.cpp b/src/intel/compiler/brw_shader.cpp
index 792b0572493..e0b2b167060 100644
--- a/src/intel/compiler/brw_shader.cpp
+++ b/src/intel/compiler/brw_shader.cpp
@@ -974,6 +974,8 @@ backend_instruction::can_do_source_mods() const
    case SHADER_OPCODE_CLUSTER_BROADCAST:
    case SHADER_OPCODE_MOV_INDIRECT:
    case SHADER_OPCODE_SHUFFLE:
+   case SHADER_OPCODE_INT_QUOTIENT:
+   case SHADER_OPCODE_INT_REMAINDER:
       return false;
    default:
       return true;