On 07/05/2011 03:07 PM, Paul Berry wrote:
Previously, lower_jumps.cpp only lowered return statements that
appeared inside of an if statement.
Without this patch, lower_jumps.cpp might not lower certain return
statements, causing some back-ends to fail (as in bug #36669).
Fixes unit test test_lower_returns_1.
---
src/glsl/lower_jumps.cpp | 15 +++++++++++++++
1 files changed, 15 insertions(+), 0 deletions(-)
diff --git a/src/glsl/lower_jumps.cpp b/src/glsl/lower_jumps.cpp
index fa247c6..73b5d57 100644
--- a/src/glsl/lower_jumps.cpp
+++ b/src/glsl/lower_jumps.cpp
@@ -851,6 +851,21 @@ lower_continue:
*/
visit_block(&ir->body);
+ /* If the body ended in an unconditional return of non-void,
+ * then we don't need to lower it because an unconditional
+ * return of non-void at the end of a function is what returns
+ * get lowered to.
This comment doesn't make sense to me. Are you trying to say that
unconditional all non-void returns were already lowered to variable
assignments and void returns? Or...?
+ *
+ * If the body ended in a return of void, eliminate it because
+ * it is redundant.
+ */
+ if (ir->return_type->is_void()&&
+ get_jump_strength((ir_instruction *) ir->body.get_tail())) {
+ ir_jump *jump = (ir_jump *) ir->body.get_tail();
+ assert (jump->ir_type == ir_type_return);
+ jump->remove();
+ }
+
if(this->function.return_value)
ir->body.push_tail(new(ir) ir_return(new (ir)
ir_dereference_variable(this->function.return_value)));
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