r600/sb: Do not distribute neg in expr_handler::fold_assoc() when folding multiplicat...

Previously it was doing this transformation for a Trine 3 shader:
     MUL     R6.x.12,    R13.x.23, 0.5|3f000000
-    MULADD     R4.x.12,    -R6.x.12, 2|40000000, 1|3f800000
+    MULADD     R4.x.12,    -R13.x.23, -1|bf800000, 1|3f800000

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94412
Signed-off-by: Xavier Bouchoux <xavierb@gmail.com>
Cc: "11.0 11.1 11.2" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Glenn Kennard <glenn.kennard@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/src/gallium/drivers/r600/sb/sb_expr.cpp b/src/gallium/drivers/r600/sb/sb_expr.cpp
index 556a05da39558d69d12675da74b5b236398c8f07..3dd3a4815ba0e174df95fd1154caf8a1fede589a 100644 (file)
--- a/src/gallium/drivers/r600/sb/sb_expr.cpp
+++ b/src/gallium/drivers/r600/sb/sb_expr.cpp
@@ -598,9 +598,13 @@ bool expr_handler::fold_assoc(alu_node *n) {
 
        unsigned op = n->bc.op;
        bool allow_neg = false, cur_neg = false;
+       bool distribute_neg = false;
 
        switch(op) {
        case ALU_OP2_ADD:
+               distribute_neg = true;
+               allow_neg = true;
+               break;
        case ALU_OP2_MUL:
        case ALU_OP2_MUL_IEEE:
                allow_neg = true;
@@ -632,7 +636,7 @@ bool expr_handler::fold_assoc(alu_node *n) {
                if (v1->is_const()) {
                        literal arg = v1->get_const_value();
                        apply_alu_src_mod(a->bc, 1, arg);
-                       if (cur_neg)
+                       if (cur_neg && distribute_neg)
                                arg.f = -arg.f;
 
                        if (a == n)
@@ -660,7 +664,7 @@ bool expr_handler::fold_assoc(alu_node *n) {
                if (v0->is_const()) {
                        literal arg = v0->get_const_value();
                        apply_alu_src_mod(a->bc, 0, arg);
-                       if (cur_neg)
+                       if (cur_neg && distribute_neg)
                                arg.f = -arg.f;
 
                        if (last_arg == 0) {