[Mesa-dev] [PATCH] r600/sb: handle jump after target to end of program. (v2)

[Dave Airlie]

From: Dave Airlie <airlied at redhat.com>

This fixes hangs on cayman with
tests/spec/arb_tessellation_shader/execution/trivial-tess-gs_no-gs-inputs.shader_test

This has a single if/else in it, and when this peephole activated,
it would set the jump target to NULL if there was no instruction
after the final POP. This adds a NOP if we get a jump in this case,
and seems to fix the hangs, so we have a valid target for the ELSE
instruction to go to, instead of 0 (which causes infinite loops).

v2: update last_cf correctly. (I had some other patches hide this)

Cc: <mesa-stable at lists.freedesktop.org>
Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 src/gallium/drivers/r600/sb/sb_bc_finalize.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/gallium/drivers/r600/sb/sb_bc_finalize.cpp b/src/gallium/drivers/r600/sb/sb_bc_finalize.cpp
index 82826a9092..7f1dd0a7a0 100644
--- a/src/gallium/drivers/r600/sb/sb_bc_finalize.cpp
+++ b/src/gallium/drivers/r600/sb/sb_bc_finalize.cpp
@@ -933,6 +933,11 @@ void bc_finalizer::cf_peephole() {
 		cf_node *c = static_cast<cf_node*>(*I);
 
 		if (c->jump_after_target) {
+			if (c->jump_target->next == NULL) {
+				c->jump_target->insert_after(sh.create_cf(CF_OP_NOP));
+				if (last_cf == c->jump_target)
+					last_cf = static_cast<cf_node*>(c->jump_target->next);
+			}
 			c->jump_target = static_cast<cf_node*>(c->jump_target->next);
 			c->jump_after_target = false;
 		}
-- 
2.14.3