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authorTimothy Arceri <tarceri@itsqueeze.com>2018-03-26 10:31:26 +1100
committerJuan A. Suarez Romero <jasuarez@igalia.com>2018-04-12 21:49:30 +0200
commit7fe3731e9fa884d1b449af3dd8706aec3970ef77 (patch)
tree98bd1b874a7da4467410eeff21cd062e71f0d46a
parent4cfb3553eb40b26c1c2931e13136c2ceb216e114 (diff)
glsl: fix infinite loop caused by bug in loop unrolling pass
Just checking for 2 jumps is not enough to be sure we can do a complex loop unroll. We need to make sure we also have also found 2 loop terminators. Without this we were attempting to unroll a loop where the second jump was nested inside multiple ifs which loop analysis is unable to detect as a terminator. We ended up splicing out the first terminator but failed to actually unroll the loop, this resulted in the creation of a possible infinite loop. Fixes: 646621c66da9 "glsl: make loop unrolling more like the nir unrolling path" Tested-by: Gert Wollny <gw.fossdev@gmail.com> Reviewed-by: Ian Romanick <ian.d.romanick@intel.com> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105670 (cherry picked from commit 56b867395dee1a48594b27987d3bf68a4e745dda) Squashed with: glsl: remove unreachable assert() Earlier commit enforced that we'll bail out if the number of terminators is different than 2. With that in mind, the assert() will never trigger. Fixes: 56b867395de ("glsl: fix infinite loop caused by bug in loop unrolling pass") Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com> Signed-off-by: Emil Velikov <emil.velikov@collabora.com> (cherry picked from commit 8eceac9de7d3cd4fddabbe61d512acfed9812169)
-rw-r--r--src/compiler/glsl/loop_unroll.cpp4
1 files changed, 1 insertions, 3 deletions
diff --git a/src/compiler/glsl/loop_unroll.cpp b/src/compiler/glsl/loop_unroll.cpp
index 6e06a30fb91..874f4185681 100644
--- a/src/compiler/glsl/loop_unroll.cpp
+++ b/src/compiler/glsl/loop_unroll.cpp
@@ -519,7 +519,7 @@ loop_unroll_visitor::visit_leave(ir_loop *ir)
* isn't any additional unknown terminators, or any other jumps nested
* inside futher ifs.
*/
- if (ls->num_loop_jumps != 2)
+ if (ls->num_loop_jumps != 2 || ls->terminators.length() != 2)
return visit_continue;
ir_instruction *first_ir =
@@ -528,8 +528,6 @@ loop_unroll_visitor::visit_leave(ir_loop *ir)
unsigned term_count = 0;
bool first_term_then_continue = false;
foreach_in_list(loop_terminator, t, &ls->terminators) {
- assert(term_count < 2);
-
ir_if *ir_if = t->ir->as_if();
assert(ir_if != NULL);