diff options
| -rw-r--r-- | src/compiler/glsl/loop_unroll.cpp | 30 |
1 files changed, 26 insertions, 4 deletions
diff --git a/src/compiler/glsl/loop_unroll.cpp b/src/compiler/glsl/loop_unroll.cpp index aea2743cdb1..bc377dff3b9 100644 --- a/src/compiler/glsl/loop_unroll.cpp +++ b/src/compiler/glsl/loop_unroll.cpp @@ -315,11 +315,33 @@ loop_unroll_visitor::visit_leave(ir_loop *ir) return visit_continue; } - /* Don't try to unroll loops where the number of iterations is not known - * at compile-time. - */ - if (ls->limiting_terminator == NULL) + if (ls->limiting_terminator == NULL) { + ir_instruction *last_ir = + (ir_instruction *) ir->body_instructions.get_tail(); + + /* If a loop has no induction variable and the last instruction is + * a break, unroll the loop with a count of 1. This is the classic + * + * do { + * // ... + * } while (false) + * + * that is used to wrap multi-line macros. + * + * If num_loop_jumps is not zero, last_ir cannot be NULL... there has to + * be at least num_loop_jumps instructions in the loop. + */ + if (ls->num_loop_jumps == 1 && is_break(last_ir)) { + last_ir->remove(); + + simple_unroll(ir, 1); + } + + /* Don't try to unroll loops where the number of iterations is not known + * at compile-time. + */ return visit_continue; + } iterations = ls->limiting_terminator->iterations; |