pru: Implement TARGET_CLASS_LIKELY_SPILLED_P to fix PR115013

Commit r15-436-g44e7855e did not fix PR115013 for PRU because
SMALL_REGISTER_CLASS_P is not returning an accurate value for the PRU
backend.

Word mode for PRU backend is defined as 8-bit, yet all ALU operations
are preferred in 32-bit mode.  Thus checking whether a register class
contains a single word_mode register would not classify the actually
single SImode register classes as small.  This affected the
multiplication source and destination register classes.

Fix by implementing TARGET_CLASS_LIKELY_SPILLED_P to treat all register
classes with SImode or smaller size as likely spilled.  This in turn
corrects the behaviour of SMALL_REGISTER_CLASS_P for PRU.

	PR rtl-optimization/115013

gcc/ChangeLog:

	* config/pru/pru.cc (pru_class_likely_spilled_p): Implement
	to mark classes containing one SImode register as likely
	spilled.
	(TARGET_CLASS_LIKELY_SPILLED_P): Define.

Signed-off-by: Dimitar Dimitrov <dimitar@dinux.eu>

diff --git a/gcc/config/pru/pru.cc b/gcc/config/pru/pru.cc
index 41d7195d2b5504555fe7a8e59f88981ef78d30b7..491f66432b372e6d862418424cb8b60d76d9987a 100644 (file)
--- a/gcc/config/pru/pru.cc
+++ b/gcc/config/pru/pru.cc
@@ -517,6 +517,17 @@ pru_can_use_return_insn (void)
   return cfun->machine->total_size == 0;
 }
 \f
+/* Implement `TARGET_CLASS_LIKELY_SPILLED_P'.  The original intention
+   of the default implementation is kept, but is adjusted for PRU.
+   Return TRUE if the given class C contains a single SImode
+   (as opposed to word_mode!) register.  */
+
+static bool
+pru_class_likely_spilled_p (reg_class_t c)
+{
+  return (reg_class_size[(int) c] <= GET_MODE_SIZE (SImode));
+}
+
 /* Implement TARGET_HARD_REGNO_MODE_OK.  */
 
 static bool
@@ -3181,6 +3192,9 @@ pru_unwind_word_mode (void)
 #undef TARGET_CAN_ELIMINATE
 #define TARGET_CAN_ELIMINATE pru_can_eliminate
 
+#undef TARGET_CLASS_LIKELY_SPILLED_P
+#define TARGET_CLASS_LIKELY_SPILLED_P pru_class_likely_spilled_p
+
 #undef TARGET_HARD_REGNO_MODE_OK
 #define TARGET_HARD_REGNO_MODE_OK pru_hard_regno_mode_ok