intel/fs: Don't copy propagate from saturate to sel

There are already NIR algebraic optimizations (see also ac6646129f7
("nir: Move fsat outside of fmin/fmax if second arg is 0 to 1.") that
will try to remove the saturate from things like

    fmax(0.5, fsat(x))

This basically reverts 40aeb558ce8 ("i965/fs: Allow propagation of
instructions with saturate flag to sel"). That commit message had no
shader-db information, so it's unclear whether this actually helped
anything ever.

No shader-db changes on any Intel platform.

One shader in Far Cry New Dawn was affected.

Cycles in all programs: 10933090738 -> 10933090736 (-0.0%)
Cycles helped: 1

Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22169>

2 files changed, 7 insertions, 29 deletions

diff --git a/src/intel/compiler/brw_fs_copy_propagation.cpp b/src/intel/compiler/brw_fs_copy_propagation.cpp
index 60603ba4557..05556943dfc 100644
--- a/src/intel/compiler/brw_fs_copy_propagation.cpp
+++ b/src/intel/compiler/brw_fs_copy_propagation.cpp
@@ -51,7 +51,6 @@ struct acp_entry : public exec_node {
    unsigned size_written;
    unsigned size_read;
    enum opcode opcode;
-   bool saturate;
    bool is_partial_write;
    bool force_writemask_all;
 };
@@ -722,22 +721,6 @@ fs_visitor::try_copy_propagate(fs_inst *inst, int arg, acp_entry *entry)
       return false;
    }
 
-   if (entry->saturate) {
-      switch(inst->opcode) {
-      case BRW_OPCODE_SEL:
-         if ((inst->conditional_mod != BRW_CONDITIONAL_GE &&
-              inst->conditional_mod != BRW_CONDITIONAL_L) ||
-             inst->src[1].file != IMM ||
-             inst->src[1].f < 0.0 ||
-             inst->src[1].f > 1.0) {
-            return false;
-         }
-         break;
-      default:
-         return false;
-      }
-   }
-
    /* Save the offset of inst->src[arg] relative to entry->dst for it to be
     * applied later.
     */
@@ -772,9 +755,6 @@ fs_visitor::try_copy_propagate(fs_inst *inst, int arg, acp_entry *entry)
       inst->src[arg].stride *= entry->src.stride;
    }
 
-   /* Compose any saturate modifiers. */
-   inst->saturate = inst->saturate || entry->saturate;
-
    /* Compute the first component of the copy that the instruction is
     * reading, and the base byte offset within that component.
     */
@@ -821,8 +801,6 @@ fs_visitor::try_constant_propagate(fs_inst *inst, acp_entry *entry)
       return false;
    if (type_sz(entry->src.type) > 4)
       return false;
-   if (entry->saturate)
-      return false;
 
    for (int i = inst->sources - 1; i >= 0; i--) {
       if (inst->src[i].file != VGRF)
@@ -1105,6 +1083,7 @@ can_propagate_from(fs_inst *inst)
             (inst->src[0].file == FIXED_GRF &&
              inst->src[0].is_contiguous())) &&
            inst->src[0].type == inst->dst.type &&
+           !inst->saturate &&
            /* Subset of !is_partial_write() conditions. */
            !((inst->predicate && inst->opcode != BRW_OPCODE_SEL) ||
              !inst->dst.is_contiguous())) ||
@@ -1168,7 +1147,6 @@ fs_visitor::opt_copy_propagation_local(void *copy_prop_ctx, bblock_t *block,
          for (unsigned i = 0; i < inst->sources; i++)
             entry->size_read += inst->size_read(i);
          entry->opcode = inst->opcode;
-         entry->saturate = inst->saturate;
          entry->is_partial_write = inst->is_partial_write();
          entry->force_writemask_all = inst->force_writemask_all;
          acp[entry->dst.nr % ACP_HASH_SIZE].push_tail(entry);
diff --git a/src/intel/compiler/test_fs_copy_propagation.cpp b/src/intel/compiler/test_fs_copy_propagation.cpp
index 2de13476032..c66f64fd139 100644
--- a/src/intel/compiler/test_fs_copy_propagation.cpp
+++ b/src/intel/compiler/test_fs_copy_propagation.cpp
@@ -164,12 +164,12 @@ TEST_F(copy_propagation_test, maxmax_sat_imm)
       bool expected_result;
    } test[] = {
       /*   conditional mod,     imm, expected_result */
-      { BRW_CONDITIONAL_GE  ,  0.1f, true },
-      { BRW_CONDITIONAL_L   ,  0.1f, true },
-      { BRW_CONDITIONAL_GE  ,  0.5f, true },
-      { BRW_CONDITIONAL_L   ,  0.5f, true },
-      { BRW_CONDITIONAL_GE  ,  0.9f, true },
-      { BRW_CONDITIONAL_L   ,  0.9f, true },
+      { BRW_CONDITIONAL_GE  ,  0.1f, false },
+      { BRW_CONDITIONAL_L   ,  0.1f, false },
+      { BRW_CONDITIONAL_GE  ,  0.5f, false },
+      { BRW_CONDITIONAL_L   ,  0.5f, false },
+      { BRW_CONDITIONAL_GE  ,  0.9f, false },
+      { BRW_CONDITIONAL_L   ,  0.9f, false },
       { BRW_CONDITIONAL_GE  , -1.5f, false },
       { BRW_CONDITIONAL_L   , -1.5f, false },
       { BRW_CONDITIONAL_GE  ,  1.5f, false },