https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69336
Bug ID: 69336
Summary: Constant value not detected
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: enhancement
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: glisse at gcc dot gnu.org
Target Milestone: ---
Created attachment 37384
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37384&action=edit
testcase
This code was posted on the boost ML for unrelated reasons, I just commented
out the last line. Compiling with -O3, I would expect the whole thing to
compile to nothing, but instead I get in the .optimized dump the rather sad:
cmap._values[1].second.second = "pear";
_12 = MEM[(const char * const &)&cmap]._values[1].second.second;
if (_12 == 0B)
I didn't check, it might be that just one more pass would get it, dom3 is quite
busy on this example, but unless we intend to loop on passes, I believe we
should have optimized this already in some earlier pass. I am sure there are
already several PRs about similar issues, feel free to close this one if it
seems too redundant.
