[Mesa-dev] [PATCH v3 13/48] intel/fs: Use the original destination region for int MUL lowering

[Jason Ekstrand]

Some hardware (CHV, BXT) have special restrictions on register regions
when doing integer multiplication.  We want to respect those when we
lower to DxW multiplication.

Cc: mesa-stable at lists.freedesktop.org
---
 src/intel/compiler/brw_fs.cpp | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/intel/compiler/brw_fs.cpp b/src/intel/compiler/brw_fs.cpp
index 56455e9..1c4351b 100644
--- a/src/intel/compiler/brw_fs.cpp
+++ b/src/intel/compiler/brw_fs.cpp
@@ -3482,18 +3482,20 @@ fs_visitor::lower_integer_multiplication()
 
             bool needs_mov = false;
             fs_reg orig_dst = inst->dst;
+            fs_reg low = inst->dst;
             if (orig_dst.is_null() || orig_dst.file == MRF ||
                 regions_overlap(inst->dst, inst->size_written,
                                 inst->src[0], inst->size_read(0)) ||
                 regions_overlap(inst->dst, inst->size_written,
                                 inst->src[1], inst->size_read(1))) {
                needs_mov = true;
-               inst->dst = fs_reg(VGRF, alloc.allocate(dispatch_width / 8),
-                                  inst->dst.type);
+               low.nr = alloc.allocate(regs_written(inst));
+               low.offset = low.offset % REG_SIZE;
             }
-            fs_reg low = inst->dst;
-            fs_reg high(VGRF, alloc.allocate(dispatch_width / 8),
-                        inst->dst.type);
+
+            fs_reg high = inst->dst;
+            high.nr = alloc.allocate(regs_written(inst));
+            high.offset = high.offset % REG_SIZE;
 
             if (devinfo->gen >= 7) {
                if (inst->src[1].file == IMM) {
@@ -3514,13 +3516,13 @@ fs_visitor::lower_integer_multiplication()
                         inst->src[1]);
             }
 
-            ibld.ADD(subscript(inst->dst, BRW_REGISTER_TYPE_UW, 1),
+            ibld.ADD(subscript(low, BRW_REGISTER_TYPE_UW, 1),
                      subscript(low, BRW_REGISTER_TYPE_UW, 1),
                      subscript(high, BRW_REGISTER_TYPE_UW, 0));
 
             if (needs_mov || inst->conditional_mod) {
                set_condmod(inst->conditional_mod,
-                           ibld.MOV(orig_dst, inst->dst));
+                           ibld.MOV(orig_dst, low));
             }
          }
 
-- 
2.5.0.400.gff86faf