re PR middle-end/20396 (TRULY_NOOP_TRUNCATION ignored)

2005-08-16  J"orn Rennecke <joern.rennecke@st.com>
            Richard Shann <rshann@superh.com>

	PR middle-end/20396:
	* optabs.c (expand_binop): Take TRULY_NOOP_TRUNCATION into account.

Co-Authored-By: Richard Shann <rshann@superh.com>
From-SVN: r103153

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index c9df105..9d613e4 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2005-08-16  J"orn Rennecke <joern.rennecke@st.com>
+            Richard Shann <rshann@superh.com>
+
+       PR middle-end/20396:
+       * optabs.c (expand_binop): Take TRULY_NOOP_TRUNCATION into account.
+
 2005-08-16  Sebastian Pop  <pop@cri.ensmp.fr>
 
        * tree-ssa-loop-niter.c (scev_probably_wraps_p): Reword a comment.

diff --git a/gcc/optabs.c b/gcc/optabs.c
index 466a56c..9f73ac1 100644 (file)
--- a/gcc/optabs.c
+++ b/gcc/optabs.c
@@ -1184,7 +1184,9 @@ expand_binop (enum machine_mode mode, optab binoptab, rtx op0, rtx op1,
 
       if (temp != 0)
        {
-         if (GET_MODE_CLASS (mode) == MODE_INT)
+         if (GET_MODE_CLASS (mode) == MODE_INT
+             && TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (mode),
+                                        GET_MODE_BITSIZE (GET_MODE (temp))))
            return gen_lowpart (mode, temp);
          else
            return convert_to_mode (mode, temp, unsignedp);
@@ -1231,7 +1233,9 @@ expand_binop (enum machine_mode mode, optab binoptab, rtx op0, rtx op1,
                                 unsignedp, OPTAB_DIRECT);
            if (temp)
              {
-               if (class != MODE_INT)
+               if (class != MODE_INT
+                    || !TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (mode),
+                                               GET_MODE_BITSIZE (wider_mode)))
                  {
                    if (target == 0)
                      target = gen_reg_rtx (mode);
@@ -1759,7 +1763,9 @@ expand_binop (enum machine_mode mode, optab binoptab, rtx op0, rtx op1,
                                   unsignedp, methods);
              if (temp)
                {
-                 if (class != MODE_INT)
+                 if (class != MODE_INT
+                     || !TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (mode),
+                                                GET_MODE_BITSIZE (wider_mode)))
                    {
                      if (target == 0)
                        target = gen_reg_rtx (mode);