The following patch fixes:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58785
LRA chooses constraint 'm' for const_int operand. It means that the
const_int should be placed in memory but it does not happen as preferred
reload class hook returns LO_REGS for class NO_REGS which is result of
LRA choosing 'm'. I don't know why reload pass needs such value but it
should be return NO_REGS IMHO as it results in much less reload insns.
Is this patch ok to commit to the trunk?
2013-10-30 Vladimir Makarov <[email protected]>
PR target/58785
* config/arm/arm.c (arm_preferred_reload_class): Don't return
LO_REGS for NO_REGS for LRA.
2013-10-30 Vladimir Makarov <[email protected]>
PR target/58785
* gcc.target/arm/pr58785.c: New.
Index: config/arm/arm.c
===================================================================
--- config/arm/arm.c (revision 204213)
+++ config/arm/arm.c (working copy)
@@ -6884,7 +6884,7 @@ arm_preferred_reload_class (rtx x ATTRIB
{
if (rclass == GENERAL_REGS
|| rclass == HI_REGS
- || rclass == NO_REGS
+ || (! lra_in_progress && rclass == NO_REGS)
|| rclass == STACK_REG)
return LO_REGS;
else
Index: testsuite/gcc.target/arm/pr58785.c
===================================================================
--- testsuite/gcc.target/arm/pr58785.c (revision 0)
+++ testsuite/gcc.target/arm/pr58785.c (working copy)
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mthumb" } */
+
+typedef _Fract HQtype __attribute__ ((mode (HQ)));
+extern void *memcpy (void *,const void *,int);
+
+HQtype f()
+{
+ HQtype c;
+ int z = 0xfada;
+ memcpy (&c, &z, 2);
+ return c;
+}
