On 03/04/15 12:50, Steve Ellcey wrote:
While examining some MIPS code I noticed that GCC did not seem to be fully honoring the aligned attribute on some local variables. I submitted PR middle-end/65315 to record the bug and I think I now understand it and have a fix. The problem was that expand_stack_vars seemed to think that the first entry in stack_vars_sorted would have the largest alignment but while all the variables that had alignment greater then MAX_SUPPORTED_STACK_ALIGNMENT would come before all variables whose alignment was less than MAX_SUPPORTED_STACK_ALIGNMENT, within the variables with the alignment greater than MAX_SUPPORTED_STACK_ALIGNMENT, they were sorted by size, not by alignment.So my fix was to update large_align in expand_stack_vars if needed. I have verified the fix on the MIPS test case in PR 65315 and am doing a regression test now. OK to checkin if there are no regressions? I wasn't sure how to create a generic test case, I was checking the alignment on MIPS by hand by looking for the shift-right/shift-left instructions that create an aligned pointer but that obviously doesn't work on other architectures. Steve Ellcey sell...@imgtec.com 2015-03-04 Steve Ellcey <sell...@imgtec.com> PR middle-end/65315 * cfgexpand.c (expand_stack_vars): Update large_align to maximum needed alignment.
Please include a testcase for the testsuite if at all possible. OK for the trunk. jeff
