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* [gcc(refs/users/guojiufu/heads/personal-branch)] Fix 92085-2.c ICE due to having (const_int 0) as the destination of a set.
@ 2020-06-10 3:22 Jiu Fu Guo
0 siblings, 0 replies; only message in thread
From: Jiu Fu Guo @ 2020-06-10 3:22 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:c7969df1c5d3785c0b409f97e7682a6f0d2637ec
commit c7969df1c5d3785c0b409f97e7682a6f0d2637ec
Author: Jeff Law <law@torsion.usersys.redhat.com>
Date: Mon Jun 1 17:14:50 2020 -0400
Fix 92085-2.c ICE due to having (const_int 0) as the destination of a set.
gcc/
* lower-subreg.c (resolve_simple_move): If simplify_gen_subreg_concatn
returns (const_int 0) for the destination, then emit nothing.
Diff:
---
gcc/lower-subreg.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/gcc/lower-subreg.c b/gcc/lower-subreg.c
index a11e535b5bf..abe7180c686 100644
--- a/gcc/lower-subreg.c
+++ b/gcc/lower-subreg.c
@@ -1087,12 +1087,21 @@ resolve_simple_move (rtx set, rtx_insn *insn)
emit_clobber (dest);
for (i = 0; i < words; ++i)
- emit_move_insn (simplify_gen_subreg_concatn (word_mode, dest,
- dest_mode,
- i * UNITS_PER_WORD),
- simplify_gen_subreg_concatn (word_mode, src,
- orig_mode,
- i * UNITS_PER_WORD));
+ {
+ rtx t = simplify_gen_subreg_concatn (word_mode, dest,
+ dest_mode,
+ i * UNITS_PER_WORD);
+ /* simplify_gen_subreg_concatn can return (const_int 0) for
+ some sub-objects of paradoxical subregs. As a source operand,
+ that's fine. As a destination it must be avoided. Those are
+ supposed to be don't care bits, so we can just drop that store
+ on the floor. */
+ if (t != CONST0_RTX (word_mode))
+ emit_move_insn (t,
+ simplify_gen_subreg_concatn (word_mode, src,
+ orig_mode,
+ i * UNITS_PER_WORD));
+ }
}
if (real_dest != NULL_RTX)
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