diff options
author | Bernd Schmidt <bernds@codesourcery.com> | 2010-06-29 13:51:37 +0000 |
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committer | Bernd Schmidt <bernds@codesourcery.com> | 2010-06-29 13:51:37 +0000 |
commit | 2db5fbcdab3cedfe388523ee30e566a8e3b1ef49 (patch) | |
tree | 6f4891ddd4a72cde06b176e32e7c65dcb748eeaf /gcc/cse.c | |
parent | 28a022725cdf35b57ed5ae759a99003e315ae376 (diff) |
Revert parts of the change for PR25130.
* cse.c (exp_equiv_p): For MEMs, if for_gcse, only compare
MEM_ALIAS_SET.
git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@161534 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/cse.c')
-rw-r--r-- | gcc/cse.c | 22 |
1 files changed, 6 insertions, 16 deletions
diff --git a/gcc/cse.c b/gcc/cse.c index 43072b34012..82921f66861 100644 --- a/gcc/cse.c +++ b/gcc/cse.c @@ -2669,26 +2669,16 @@ exp_equiv_p (const_rtx x, const_rtx y, int validate, bool for_gcse) case MEM: if (for_gcse) { + /* Can't merge two expressions in different alias sets, since we + can decide that the expression is transparent in a block when + it isn't, due to it being set with the different alias set. */ + if (MEM_ALIAS_SET (x) != MEM_ALIAS_SET (y)) + return 0; + /* A volatile mem should not be considered equivalent to any other. */ if (MEM_VOLATILE_P (x) || MEM_VOLATILE_P (y)) return 0; - - /* Can't merge two expressions in different alias sets, since we - can decide that the expression is transparent in a block when - it isn't, due to it being set with the different alias set. - - Also, can't merge two expressions with different MEM_ATTRS. - They could e.g. be two different entities allocated into the - same space on the stack (see e.g. PR25130). In that case, the - MEM addresses can be the same, even though the two MEMs are - absolutely not equivalent. - - But because really all MEM attributes should be the same for - equivalent MEMs, we just use the invariant that MEMs that have - the same attributes share the same mem_attrs data structure. */ - if (MEM_ATTRS (x) != MEM_ATTRS (y)) - return 0; } break; |