Hello!
We can exit early from var_lowpart for matched modes. This avoids
situation, where var_lowpart tries to change
(gdb) p debug_rtx (incoming)
(concat:SC (reg:SF 48 $f16 [ x ])
(reg:SF 49 $f17 [ x+4 ]))
$1 = void
to SCmode, and returning NULL_RTX, since the RTX is neither REG, neither MEM.
2012-08-07 Uros Bizjak <ubiz...@gmail.com>
PR debug/54177
* var-tracking.c (var_lowpart): Exit early for matched modes.
Tested on x86_64-pc-linux-gnu {,-m32} and alphaev68-unknown-linux-gnu,
where the patch also fixes testsuite failure.
Patch was approved in the PR by Alexandre, and is committed to mainline SVN.
Uros.
Index: var-tracking.c
===================================================================
--- var-tracking.c (revision 190150)
+++ var-tracking.c (working copy)
@@ -5086,12 +5086,12 @@ var_lowpart (enum machine_mode mode, rtx loc)
{
unsigned int offset, reg_offset, regno;
+ if (GET_MODE (loc) == mode)
+ return loc;
+
if (!REG_P (loc) && !MEM_P (loc))
return NULL;
- if (GET_MODE (loc) == mode)
- return loc;
-
offset = byte_lowpart_offset (mode, GET_MODE (loc));
if (MEM_P (loc))
