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-rw-r--r--gcc/combine.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/gcc/combine.c b/gcc/combine.c
index e3ad70a..675b1fe 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -3394,7 +3394,16 @@ subst (x, from, to, in_dest, unique_copy)
}
else if (fmt[i] == 'e')
{
- if (COMBINE_RTX_EQUAL_P (XEXP (x, i), from))
+ /* If this is a register being set, ignore it. */
+ new = XEXP (x, i);
+ if (in_dest
+ && (code == SUBREG || code == STRICT_LOW_PART
+ || code == ZERO_EXTRACT)
+ && i == 0
+ && GET_CODE (new) == REG)
+ ;
+
+ else if (COMBINE_RTX_EQUAL_P (XEXP (x, i), from))
{
/* In general, don't install a subreg involving two
modes not tieable. It can worsen register