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S/390: Fix movqi/movhi inefficiency


Hello,

the movqi and movhi expanders would generate SIGN_EXTEND or
ZERO_EXTEND patterns to more faithfully represent the actions
of the available assembler instructions to load from memory.

However, this proved suboptimal when loading from a
(MEM (ADDRESSOF ...)), because the SIGN_EXTEND/ZERO_EXTEND
prevented replacement of the MEM with a REG, and thus 
might unnecessarily force a variable to the stack.

This patch fixes that case.   Incidentally, this fixes a
bootstrap error on s390x with Ada, because it appears to
hide another bug ...

Bootstrapped/regtested on s390-ibm-linux and s390x-ibm-linux.
Applied to CVS head.

Bye,
Ulrich 

ChangeLog:

	* config/s390/s390.md ("movhi"): Do not emit extender pattern
	when loading from a (MEM (ADDRESSOF ...)).
	("movqi"): Likewise.

Index: gcc/config/s390/s390.md
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/s390/s390.md,v
retrieving revision 1.84
diff -c -p -r1.84 s390.md
*** gcc/config/s390/s390.md	30 Oct 2003 14:11:34 -0000	1.84
--- gcc/config/s390/s390.md	28 Nov 2003 21:09:38 -0000
***************
*** 1313,1319 ****
       always sign-extends (at least) to SImode.  */
    if (optimize && !no_new_pseudos
        && register_operand (operands[0], VOIDmode)
!       && memory_operand (operands[1], VOIDmode))
      {
        rtx tmp = gen_reg_rtx (SImode);
        rtx ext = gen_rtx_SIGN_EXTEND (SImode, operands[1]);
--- 1313,1320 ----
       always sign-extends (at least) to SImode.  */
    if (optimize && !no_new_pseudos
        && register_operand (operands[0], VOIDmode)
!       && GET_CODE (operands[1]) == MEM
!       && GET_CODE (XEXP (operands[1], 0)) != ADDRESSOF)
      {
        rtx tmp = gen_reg_rtx (SImode);
        rtx ext = gen_rtx_SIGN_EXTEND (SImode, operands[1]);
***************
*** 1360,1366 ****
       is just as fast as a QImode load.  */
    if (TARGET_ZARCH && optimize && !no_new_pseudos
        && register_operand (operands[0], VOIDmode)
!       && memory_operand (operands[1], VOIDmode))
      {
        rtx tmp = gen_reg_rtx (word_mode);
        rtx ext = gen_rtx_ZERO_EXTEND (word_mode, operands[1]);
--- 1361,1368 ----
       is just as fast as a QImode load.  */
    if (TARGET_ZARCH && optimize && !no_new_pseudos
        && register_operand (operands[0], VOIDmode)
!       && GET_CODE (operands[1]) == MEM
!       && GET_CODE (XEXP (operands[1], 0)) != ADDRESSOF)
      {
        rtx tmp = gen_reg_rtx (word_mode);
        rtx ext = gen_rtx_ZERO_EXTEND (word_mode, operands[1]);
-- 
  Dr. Ulrich Weigand
  weigand@informatik.uni-erlangen.de


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