Fix performance problem on SH with unnecessary move instructions.

	* local-alloc.c (combine_regs): Don't combine if we have a hard reg
	for which CLASS_LIKELY_SPILLED_P is true.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@25644 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fc6d1ef..4f83b46 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,8 @@
 Mon Mar  8 16:04:44 1999  Jim Wilson  <wilson@cygnus.com>
 
+       * local-alloc.c (combine_regs): Don't combine if we have a hard reg
+       for which CLASS_LIKELY_SPILLED_P is true.
+
        * unroll.c (loop_iterations): Only call loop_find_equiv_value if we
        have a REG or SUBREG.
 

diff --git a/gcc/local-alloc.c b/gcc/local-alloc.c
index ea97f33..d3dde6b 100644 (file)
--- a/gcc/local-alloc.c
+++ b/gcc/local-alloc.c
@@ -1648,6 +1648,11 @@ combine_regs (usedreg, setreg, may_save_copy, insn_number, insn, already_dead)
       || ureg == sreg
       /* Don't try to connect two different hardware registers.  */
       || (ureg < FIRST_PSEUDO_REGISTER && sreg < FIRST_PSEUDO_REGISTER)
+      /* Don't use a hard reg that might be spilled.  */
+      || (ureg < FIRST_PSEUDO_REGISTER
+         && CLASS_LIKELY_SPILLED_P (REGNO_REG_CLASS (ureg)))
+      || (sreg < FIRST_PSEUDO_REGISTER
+         && CLASS_LIKELY_SPILLED_P (REGNO_REG_CLASS (sreg)))
       /* Don't connect two different machine modes if they have different
         implications as to which registers may be used.  */
       || !MODES_TIEABLE_P (GET_MODE (usedreg), GET_MODE (setreg)))