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authorEric Anholt <[email protected]>2012-01-09 13:30:55 -0800
committerEric Anholt <[email protected]>2012-01-10 16:44:16 -0800
commit057f9ae54b5efb0020cc0c049d50e778de3f3f7a (patch)
treeb18581e837e3cf54f0f0ed061ef121393c0a0d89
parent254b24f19511014cdf4741b73d69349ac9e931a2 (diff)
glsl: Fix copy_propagation_elements bug in handling self-copies.
We were doing the kill of the updated channels, then adding our copy to the list of available stuff to copy. But if the copy was updating its own source channels, we didn't notice, breaking this code: R0.xyzw = arg0 + arg1; R0.xyzw = R0.wwwx; gl_FragColor.xyzw = clamp(R0.xyzw, 0.0, 1.0); Fixes piglit glsl-copy-propagation-self-2. Reviewed-by: Kenneth Graunke <[email protected]>
-rw-r--r--src/glsl/opt_copy_propagation_elements.cpp15
1 files changed, 14 insertions, 1 deletions
diff --git a/src/glsl/opt_copy_propagation_elements.cpp b/src/glsl/opt_copy_propagation_elements.cpp
index be446bc08ba..ebfd4fd3fe1 100644
--- a/src/glsl/opt_copy_propagation_elements.cpp
+++ b/src/glsl/opt_copy_propagation_elements.cpp
@@ -461,7 +461,20 @@ ir_copy_propagation_elements_visitor::add_copy(ir_assignment *ir)
swizzle[i] = orig_swizzle[j++];
}
- entry = new(this->mem_ctx) acp_entry(lhs->var, rhs->var, ir->write_mask,
+ int write_mask = ir->write_mask;
+ if (lhs->var == rhs->var) {
+ /* If this is a copy from the variable to itself, then we need
+ * to be sure not to include the updated channels from this
+ * instruction in the set of new source channels to be
+ * copy-propagated from.
+ */
+ for (int i = 0; i < 4; i++) {
+ if (ir->write_mask & (1 << orig_swizzle[i]))
+ write_mask &= ~(1 << i);
+ }
+ }
+
+ entry = new(this->mem_ctx) acp_entry(lhs->var, rhs->var, write_mask,
swizzle);
this->acp->push_tail(entry);
}