https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64058
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |missed-optimization
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
This sounds like a TER effect - the -fdump-rtl-expand-details dump should show
differences in SSA coalescing / TER replacements.
You are talking about
-(note 291 287 289 65 [bb 65] NOTE_INSN_BASIC_BLOCK)
-(jump_insn 289 291 290 65 (set (pc)
+(note 291 287 16 65 [bb 65] NOTE_INSN_BASIC_BLOCK)
+(insn 16 291 289 65 (set (reg:SI 85 [ l1_lsm.7 ])
+ (reg:SI 113 [ u1_lsm.6 ])) /nfs/ims/home/izamyati/test_216304.c:72 -1
+ (nil))
+(jump_insn 289 16 290 65 (set (pc)
(label_ref 288)) /nfs/ims/home/izamyati/test_216304.c:72 -1
(nil)
-> 288)
which doesn't appear in the good dump - thus it looks like u1_lsm.6 and
l1_lsm.7 were coalesced there.
Btw, on trunk the testcase is now optimized to trap unconditionally with -flto
or -fwhole-program because the global vars are not initialized.
Can you check on the coalescing theory?
