* expr.c (expand_assignment): Rework address calculation for structure

        field members to expose more invariant computations to the loop
        optimizer.
        (expand_expr): Likewise.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@20705 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e6bfeb5..096ddb2 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+1998-06-22 Herman A.J. ten Brugge <Haj.Ten.Brugge@net.HCC.nl>
+
+       * expr.c (expand_assignment): Rework address calculation for structure
+       field members to expose more invariant computations to the loop
+       optimizer.
+       (expand_expr): Likewise.
+
 Wed Jun 24 22:44:22 1998  Jeffrey A Law  (law@cygnus.com)
 
        * local-alloc.c (block_alloc): Do not try to avoid false dependencies

diff --git a/gcc/expr.c b/gcc/expr.c
index ddb5bbb..91134d3 100644 (file)
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -2920,6 +2920,26 @@ expand_assignment (to, from, want_value, suggest_reg)
 #endif
            }
 
+         if (GET_CODE (to_rtx) == MEM
+             && GET_MODE (to_rtx) == BLKmode
+             && bitsize
+             && (bitpos % bitsize) == 0 
+             && (bitsize % GET_MODE_ALIGNMENT (mode1)) == 0
+             && (alignment * BITS_PER_UNIT) == GET_MODE_ALIGNMENT (mode1))
+           {
+             rtx temp = change_address (to_rtx, mode1,
+                                        plus_constant (XEXP (to_rtx, 0),
+                                                       (bitpos /
+                                                        BITS_PER_UNIT)));
+             if (GET_CODE (XEXP (temp, 0)) == REG)
+               to_rtx = temp;
+             else
+               to_rtx = change_address (to_rtx, mode1,
+                                        force_reg (GET_MODE (XEXP (temp, 0)),
+                                                   XEXP (temp, 0)));
+             bitpos = 0;
+           }
+
          to_rtx = change_address (to_rtx, VOIDmode,
                                   gen_rtx_PLUS (ptr_mode, XEXP (to_rtx, 0),
                                                 force_reg (ptr_mode, offset_rtx)));
@@ -5918,6 +5938,27 @@ expand_expr (exp, target, tmode, modifier)
 #endif
              }
 
+           if (GET_CODE (op0) == MEM
+               && GET_MODE (op0) == BLKmode
+               && bitsize
+               && (bitpos % bitsize) == 0 
+               && (bitsize % GET_MODE_ALIGNMENT (mode1)) == 0
+               && (alignment * BITS_PER_UNIT) == GET_MODE_ALIGNMENT (mode1))
+             {
+               rtx temp = change_address (op0, mode1,
+                                          plus_constant (XEXP (op0, 0),
+                                                         (bitpos /
+                                                          BITS_PER_UNIT)));
+               if (GET_CODE (XEXP (temp, 0)) == REG)
+                 op0 = temp;
+               else
+                 op0 = change_address (op0, mode1,
+                                       force_reg (GET_MODE (XEXP (temp, 0)),
+                                                  XEXP (temp, 0)));
+               bitpos = 0;
+             }
+
+
            op0 = change_address (op0, VOIDmode,
                                  gen_rtx_PLUS (ptr_mode, XEXP (op0, 0),
                                                force_reg (ptr_mode, offset_rtx)));