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emit-rtl.c (set_unique_reg_note): Discard notes with side effects.

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gcc/
	* emit-rtl.c (set_unique_reg_note): Discard notes with side effects.

From-SVN: r214609
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Richard Sandiford 2014-08-27 21:23:03 +00:00 • committed by Richard Sandiford
parent b7679d96ec
commit 109374e2fb
2 changed files with 12 additions and 0 deletions
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gcc/ChangeLog
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@ -1,3 +1,7 @@
2014-08-27 Richard Sandiford <rdsandiford@googlemail.com>
* emit-rtl.c (set_unique_reg_note): Discard notes with side effects.
2014-08-27 David Malcolm <dmalcolm@redhat.com>
* rtl.h (JUMP_LABEL_AS_INSN): New.

8
gcc/emit-rtl.c
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@ -5181,6 +5181,14 @@ set_unique_reg_note (rtx insn, enum reg_note kind, rtx datum)
It serves no useful purpose and breaks eliminate_regs. */
if (GET_CODE (datum) == ASM_OPERANDS)
return NULL_RTX;
/* Notes with side effects are dangerous. Even if the side-effect
initially mirrors one in PATTERN (INSN), later optimizations
might alter the way that the final register value is calculated
and so move or alter the side-effect in some way. The note would
then no longer be a valid substitution for SET_SRC. */
if (side_effects_p (datum))
return NULL_RTX;
break;
default: