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Postreload and STRICT_LOW_PART
- From: Andreas Schwab <schwab at linux-m68k dot org>
- To: gcc at gcc dot gnu dot org
- Date: Sun, 20 Sep 2009 18:10:28 +0200
- Subject: Postreload and STRICT_LOW_PART
Why is postreload converting (set (REGX) (CONST_INT A)) ... (set (REGX)
(CONST_INT B)) into (set (STRICT_LOW_PART (REGX)) (CONST_INT B))? That
looks like a pessimisation especially if the constants are small, since
STRICT_LOW_PART must not touch the high part. Is there a way for the
backend to stop postreload from doing this if the constants are in some
range? On the m68k, loading a constant in the range -128..127 in SI
mode is better than loading it in strict QI mode.
Andreas.
--
Andreas Schwab, schwab@linux-m68k.org
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