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| author | Richard Biener <rguenther@suse.de> | 2020-04-08 14:04:35 +0200 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2020-04-08 19:27:59 +0200 |
| commit | dd9ca9d770a18ce4b16d867f49fef3293b483ff5 (patch) | |
| tree | dbdafc5ee792be0baf32a51201ae439824356b86 | |
| parent | 7dbfcb91a87f78446c5e10582d4ea9ea168f3f98 (diff) | |
| download | gcc-dd9ca9d770a18ce4b16d867f49fef3293b483ff5.tar.gz | |
rtl-optimization/93946 - fix TBAA for redundant store removal in CSE
It turns out RTL CSE tries to remove redundant stores but fails to
do the usual validity check what such a change is TBAA neutral to
later loads.
This now triggers with the PR93946 testcases on nios2.
2020-04-08 Richard Biener <rguenther@suse.de>
PR rtl-optimization/93946
* cse.c (cse_insn): Record the tabled expression in
src_related. Verify a redundant store removal is valid.
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/cse.c | 13 |
2 files changed, 17 insertions, 2 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index ffa8930556d..025a4a67937 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2020-04-08 Richard Biener <rguenther@suse.de> + + PR rtl-optimization/93946 + * cse.c (cse_insn): Record the tabled expression in + src_related. Verify a redundant store removal is valid. + 2020-04-08 H.J. Lu <hongjiu.lu@intel.com> PR target/94417 diff --git a/gcc/cse.c b/gcc/cse.c index 3e8724b3fed..f07bbdbebad 100644 --- a/gcc/cse.c +++ b/gcc/cse.c @@ -5074,7 +5074,7 @@ cse_insn (rtx_insn *insn) to prefer it. Copy it to src_related. The code below will then give it a negative cost. */ if (GET_CODE (dest) == code && rtx_equal_p (p->exp, dest)) - src_related = dest; + src_related = p->exp; } /* Find the cheapest valid equivalent, trying all the available @@ -5332,7 +5332,16 @@ cse_insn (rtx_insn *insn) && rtx_equal_p (trial, dest) && !side_effects_p (dest) && (cfun->can_delete_dead_exceptions - || insn_nothrow_p (insn))) + || insn_nothrow_p (insn)) + /* We can only remove the later store if the earlier aliases + at least all accesses the later one. */ + && (!MEM_P (trial) + || ((MEM_ALIAS_SET (dest) == MEM_ALIAS_SET (trial) + || alias_set_subset_of (MEM_ALIAS_SET (dest), + MEM_ALIAS_SET (trial))) + && (!MEM_EXPR (trial) + || refs_same_for_tbaa_p (MEM_EXPR (trial), + MEM_EXPR (dest)))))) { SET_SRC (sets[i].rtl) = trial; noop_insn = true; |