[PATCH] ira: Skip some pseudos in move_unallocated_pseudos

["Kewen.Lin" <linkw@linux.ibm.com>]

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Hi,

This patch is to make move_unallocated_pseudos consistent
to what we have in function find_moveable_pseudos, where we
record the original pseudo into pseudo_replaced_reg only if
validate_change succeeds with newreg.  To ensure every
unallocated pseudo in move_unallocated_pseudos has expected
information, it's better to add a check and skip it if it's
unexpected.  This avoids possible ICEs in future.

btw, I happened to found this in the bootstrapping for one
experimental local patch, which is considered as impractical.

Bootstrapped/regtested on powerpc64le-linux-gnu P9.

BR,
Kewen

gcc/ChangeLog:

	* ira.c (move_unallocated_pseudos): Check other_reg and skip if
	it isn't set.

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diff --git a/gcc/ira.c b/gcc/ira.c
index 89b5df4003d..472fcf52aad 100644
--- a/gcc/ira.c
+++ b/gcc/ira.c
@@ -5111,6 +5111,11 @@ move_unallocated_pseudos (void)
       {
 	int idx = i - first_moveable_pseudo;
 	rtx other_reg = pseudo_replaced_reg[idx];
+	/* If there is no appropriate pseudo in pseudo_replaced_reg, it
+	   means validate_change fails for this new pseudo in function
+	   find_moveable_pseudos, then bypass it here.*/
+	if (!other_reg)
+	  continue;
 	rtx_insn *def_insn = DF_REF_INSN (DF_REG_DEF_CHAIN (i));
 	/* The use must follow all definitions of OTHER_REG, so we can
 	   insert the new definition immediately after any of them.  */