i965/fs: Fix constant combining for instructions that cannot accept source mods.

This is the case for SNB math instructions so we need to be careful
and insert the literal value of the immediate into the table (rather
than its absolute value) if the instruction is unable to invert the
sign of the constant on the fly.

Cc: "12.0" <[email protected]>
Reviewed-by: Jason Ekstrand <[email protected]>

1 files changed, 3 insertions, 4 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_fs_combine_constants.cpp b/src/mesa/drivers/dri/i965/brw_fs_combine_constants.cpp
index d7a1456bce0..5bd5343b8b4 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_combine_constants.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_combine_constants.cpp
@@ -147,8 +147,6 @@ struct table {
 static struct imm *
 find_imm(struct table *table, float val)
 {
-   assert(signbit(val) == 0);
-
    for (int i = 0; i < table->len; i++) {
       if (table->imm[i].val == val) {
          return &table->imm[i];
@@ -220,7 +218,8 @@ fs_visitor::opt_combine_constants()
              inst->src[i].type != BRW_REGISTER_TYPE_F)
             continue;
 
-         float val = fabsf(inst->src[i].f);
+         float val = !inst->can_do_source_mods(devinfo) ? inst->src[i].f :
+                     fabs(inst->src[i].f);
          struct imm *imm = find_imm(&table, val);
 
          if (imm) {
@@ -301,7 +300,7 @@ fs_visitor::opt_combine_constants()
          reg->stride = 0;
          reg->negate = signbit(reg->f) != signbit(table.imm[i].val);
          assert((isnan(reg->f) && isnan(table.imm[i].val)) ||
-                fabsf(reg->f) == table.imm[i].val);
+                fabsf(reg->f) == fabs(table.imm[i].val));
       }
    }