The existing AArch64 implementation of preferred_reload_class when
called with a destination regclass STACK_REG returns the wider register
class GENERAL_REG. This patch changes the behavior such that we only
return a narrower class (or NO_REGS) and never return a wider class.
I'll leave this on the list 24h before committing.
/Marcus
2013-10-16 Marcus Shawcroft <marcus.shawcr...@arm.com>
* config/aarch64/aarch64.c (aarch64_preferred_reload_class): Adjust
handling of STACK_REG.diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index da3962f..7fce7a0 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -4219,9 +4219,18 @@ aarch64_class_max_nregs (reg_class_t regclass, enum machine_mode mode)
static reg_class_t
aarch64_preferred_reload_class (rtx x, reg_class_t regclass)
{
- if (regclass == POINTER_REGS || regclass == STACK_REG)
+ if (regclass == POINTER_REGS)
return GENERAL_REGS;
+ if (regclass == STACK_REG)
+ {
+ if (REG_P(x)
+ && reg_class_subset_p (REGNO_REG_CLASS (REGNO (x)), POINTER_REGS))
+ return regclass;
+
+ return NO_REGS;
+ }
+
/* If it's an integer immediate that MOVI can't handle, then
FP_REGS is not an option, so we return NO_REGS instead. */
if (CONST_INT_P (x) && reg_class_subset_p (regclass, FP_REGS)
