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[PATCH] [LRA] Fix wrong-code PR 91109 take 2
Hi,
as discussed in the PR 91109 audit trail,
my previous patch missed a case where no spilling is necessary,
but the re-materialized instruction has now scratch regs without
a hard register assignment. And thus the LRA pass falls out of
the loop pre-maturely.
Fixed by checking for scratch regs with no assignment
and continuing the loop in that case.
Boot-strapped and reg-tested on x86_64-pc-linux-gnu and arm-linux-gnueabihf.
Is it OK for trunk?
Thanks
Bernd.
2019-08-12 Bernd Edlinger <bernd.edlinger@hotmail.de>
PR tree-optimization/91109
* lra-int.h (lra_need_for_scratch_reg_p): Declare.
* lra.c (lra): Use lra_need_for_scratch_reg_p.
* lra-spills.c (lra_need_for_scratch_reg_p): New function.
Index: gcc/lra-int.h
===================================================================
--- gcc/lra-int.h (revision 274168)
+++ gcc/lra-int.h (working copy)
@@ -396,6 +396,7 @@ extern bool lra_coalesce (void);
/* lra-spills.c: */
+extern bool lra_need_for_scratch_reg_p (void);
extern bool lra_need_for_spills_p (void);
extern void lra_spill (void);
extern void lra_final_code_change (void);
Index: gcc/lra-spills.c
===================================================================
--- gcc/lra-spills.c (revision 274168)
+++ gcc/lra-spills.c (working copy)
@@ -549,6 +549,19 @@ spill_pseudos (void)
}
}
+/* Return true if we need scratch reg assignments. */
+bool
+lra_need_for_scratch_reg_p (void)
+{
+ int i; max_regno = max_reg_num ();
+
+ for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
+ if (lra_reg_info[i].nrefs != 0 && lra_get_regno_hard_regno (i) < 0
+ && lra_former_scratch_p (i))
+ return true;
+ return false;
+}
+
/* Return true if we need to change some pseudos into memory. */
bool
lra_need_for_spills_p (void)
Index: gcc/lra.c
===================================================================
--- gcc/lra.c (revision 274168)
+++ gcc/lra.c (working copy)
@@ -2567,7 +2567,11 @@ lra (FILE *f)
lra_create_live_ranges (lra_reg_spill_p, true);
live_p = true;
if (! lra_need_for_spills_p ())
- break;
+ {
+ if (lra_need_for_scratch_reg_p ())
+ continue;
+ break;
+ }
}
lra_spill ();
/* Assignment of stack slots changes elimination offsets for