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PATCH COMMITTED: Handle SUBREG in elim_reg_cond in flow.c
- From: Ian Lance Taylor <iant at google dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: 24 Apr 2007 14:02:18 -0700
- Subject: PATCH COMMITTED: Handle SUBREG in elim_reg_cond in flow.c
While doing some testing with --enable-checking=rtl, I discovered that
some code in flow gets an RTL checking error. This is in
elim_reg_cond:
if (COMPARISON_P (x))
{
if (REGNO (XEXP (reg) == regno)
return const0_rtx;
return x;
}
X here can come from init_propagate_block_info, which does this:
if (GET_CODE (reg) == SUBREG)
reg = SUBREG_REG (reg);
...
if (inv_cond != UNKNOWN
&& REG_P (reg)
&& XEXP (cond_true, 1) == const0_rtx)
{
so it can have a subreg in the condition. Those the code above can
ask for the REGNO of a SUBREG. Without checking enabled the test does
the wrong thing, but does little harm in practice.
This patch fixes the problem. Bootstrapped and tested on
i686-pc-linux-gnu. Committed.
Ian
2007-04-24 Ian Lance Taylor <iant@google.com>
* flow.c (elim_reg_cond): Handle a comparison of a subreg.
Index: flow.c
===================================================================
--- flow.c (revision 124119)
+++ flow.c (working copy)
@@ -3437,7 +3437,13 @@ elim_reg_cond (rtx x, unsigned int regno
if (COMPARISON_P (x))
{
- if (REGNO (XEXP (x, 0)) == regno)
+ rtx reg;
+
+ reg = XEXP (x, 0);
+ if (GET_CODE (reg) == SUBREG)
+ reg = SUBREG_REG (reg);
+ gcc_assert (REG_P (reg));
+ if (REGNO (reg) == regno)
return const0_rtx;
return x;
}