PR rtl-optimization/25310

	* reload1.c (eliminate_regs_in_insn): Handle lowpart SUBREGs
	of the eliminable register when substituting into a PLUS.

	PR rtl-optimization/25310
	* gcc.c-torture/compile/pr25310.c: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@108543 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 57cdbc3..71260a2 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2005-12-14  Ulrich Weigand  <uweigand@de.ibm.com>
+
+       PR rtl-optimization/25310
+       * reload1.c (eliminate_regs_in_insn): Handle lowpart SUBREGs
+       of the eliminable register when substituting into a PLUS.
+
 2005-12-14  Jakub Jelinek  <jakub@redhat.com>
 
        PR debug/25023

diff --git a/gcc/reload1.c b/gcc/reload1.c
index 970f5ec..29da121 100644 (file)
--- a/gcc/reload1.c
+++ b/gcc/reload1.c
@@ -3006,42 +3006,57 @@ eliminate_regs_in_insn (rtx insn, int replace)
     {
       if (GET_CODE (SET_SRC (old_set)) == PLUS)
        plus_src = SET_SRC (old_set);
-      /* First see if the source is of the form (plus (reg) CST).  */
+      /* First see if the source is of the form (plus (...) CST).  */
       if (plus_src
-         && REG_P (XEXP (plus_src, 0))
-         && GET_CODE (XEXP (plus_src, 1)) == CONST_INT
-         && REGNO (XEXP (plus_src, 0)) < FIRST_PSEUDO_REGISTER)
+         && GET_CODE (XEXP (plus_src, 1)) == CONST_INT)
        plus_cst_src = plus_src;
       else if (REG_P (SET_SRC (old_set))
               || plus_src)
        {
          /* Otherwise, see if we have a REG_EQUAL note of the form
-            (plus (reg) CST).  */
+            (plus (...) CST).  */
          rtx links;
          for (links = REG_NOTES (insn); links; links = XEXP (links, 1))
            {
              if (REG_NOTE_KIND (links) == REG_EQUAL
                  && GET_CODE (XEXP (links, 0)) == PLUS
-                 && REG_P (XEXP (XEXP (links, 0), 0))
-                 && GET_CODE (XEXP (XEXP (links, 0), 1)) == CONST_INT
-                 && REGNO (XEXP (XEXP (links, 0), 0)) < FIRST_PSEUDO_REGISTER)
+                 && GET_CODE (XEXP (XEXP (links, 0), 1)) == CONST_INT)
                {
                  plus_cst_src = XEXP (links, 0);
                  break;
                }
            }
        }
+
+      /* Check that the first operand of the PLUS is a hard reg or
+        the lowpart subreg of one.  */
+      if (plus_cst_src)
+       {
+         rtx reg = XEXP (plus_cst_src, 0);
+         if (GET_CODE (reg) == SUBREG && subreg_lowpart_p (reg))
+           reg = SUBREG_REG (reg);
+
+         if (!REG_P (reg) || REGNO (reg) >= FIRST_PSEUDO_REGISTER)
+           plus_cst_src = 0;
+       }
     }
   if (plus_cst_src)
     {
       rtx reg = XEXP (plus_cst_src, 0);
       HOST_WIDE_INT offset = INTVAL (XEXP (plus_cst_src, 1));
 
+      if (GET_CODE (reg) == SUBREG)
+       reg = SUBREG_REG (reg);
+
       for (ep = reg_eliminate; ep < &reg_eliminate[NUM_ELIMINABLE_REGS]; ep++)
        if (ep->from_rtx == reg && ep->can_eliminate)
          {
+           rtx to_rtx = ep->to_rtx;
            offset += ep->offset;
 
+           if (GET_CODE (XEXP (plus_cst_src, 0)) == SUBREG)
+             to_rtx = gen_lowpart (GET_MODE (XEXP (plus_cst_src, 0)),
+                                   to_rtx);
            if (offset == 0)
              {
                int num_clobbers;
@@ -3051,7 +3066,7 @@ eliminate_regs_in_insn (rtx insn, int replace)
                   There's not much we can do if that doesn't work.  */
                PATTERN (insn) = gen_rtx_SET (VOIDmode,
                                              SET_DEST (old_set),
-                                             ep->to_rtx);
+                                             to_rtx);
                num_clobbers = 0;
                INSN_CODE (insn) = recog (PATTERN (insn), insn, &num_clobbers);
                if (num_clobbers)
@@ -3081,7 +3096,7 @@ eliminate_regs_in_insn (rtx insn, int replace)
                PATTERN (insn) = new_body;
                old_set = single_set (insn);
 
-               XEXP (SET_SRC (old_set), 0) = ep->to_rtx;
+               XEXP (SET_SRC (old_set), 0) = to_rtx;
                XEXP (SET_SRC (old_set), 1) = GEN_INT (offset);
              }
            else

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 15f48b3..85a4828 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2005-12-14  Ulrich Weigand  <uweigand@de.ibm.com>
+
+       PR rtl-optimization/25310
+       * gcc.c-torture/compile/pr25310.c: New test.
+
 2005-12-14  Jakub Jelinek  <jakub@redhat.com>
 
        PR debug/25023

diff --git a/gcc/testsuite/gcc.c-torture/compile/pr25310.c b/gcc/testsuite/gcc.c-torture/compile/pr25310.c
new file mode 100644 (file)
index 0000000..4cd3087
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr25310.c
@@ -0,0 +1,17 @@
+
+extern int f (char *, int);
+
+void test (void)
+{
+  char buffer[65536];
+  char *bufptr;
+  char *bufend;
+  int bytes;
+
+  bufptr = buffer;
+  bufend = buffer + sizeof(buffer) - 1;
+
+  while ((bytes = f (bufptr, bufend - bufptr)) > 0)
+    bufptr += bytes;
+}
+