(output_stack_adjust): Reorganize code for readability.

If size is negative, negate and subtract it instead of adding it.

From-SVN: r13847

diff --git a/gcc/config/sh/sh.c b/gcc/config/sh/sh.c
index 12a49caa78b2fb04395ec18fe2e9662a103cfc99..dd540b773107f90579439597041e6b421fab7d8c 100644 (file)
--- a/gcc/config/sh/sh.c
+++ b/gcc/config/sh/sh.c
@@ -2485,38 +2485,42 @@ output_stack_adjust (size, reg, temp)
 {
   if (size)
     {
-      rtx val = GEN_INT (size);
-      rtx insn;
-
-      if (! CONST_OK_FOR_I (size))
+      if (CONST_OK_FOR_I (size))
+       emit_insn (gen_addsi3 (reg, reg, GEN_INT (size)));
+      /* Try to do it with two partial adjustments; however, we must make
+        sure that the stack is properly aligned at all times, in case
+        an interrupt occurs between the two partial adjustments. */
+      else if (CONST_OK_FOR_I (size / 2 & -4)
+              && CONST_OK_FOR_I (size - (size / 2 & -4)))
+       {
+         emit_insn (gen_addsi3 (reg, reg, GEN_INT (size / 2 & -4)));
+         emit_insn (gen_addsi3 (reg, reg, GEN_INT (size - (size / 2 & -4))));
+       }
+      else
        {
-         /* Try to do it with two partial adjustments; however, must make
-            sure that the stack is properly aligned at all times, in case
-            an interrupt occurs between the two partial adjustments. */
-         if (CONST_OK_FOR_I (size / 2 & -4)
-             && CONST_OK_FOR_I (size - (size / 2 & -4)))
+         rtx const_reg;
+
+         /* If TEMP is invalid, we could temporarily save a general
+            register to MACL.  However, there is currently no need
+            to handle this case, so just abort when we see it.  */
+         if (temp < 0)
+           abort ();
+         const_reg = gen_rtx (REG, SImode, temp);
+
+         /* If SIZE is negative, subtract the positive value.
+            This sometimes allows a constant pool entry to be shared
+            between prologue and epilogue code.  */
+         if (size < 0)
            {
-             val = GEN_INT (size / 2 & -4);
-             emit_insn (gen_addsi3 (reg, reg, val));
-             val = GEN_INT (size - (size / 2 & -4));
+             emit_insn (gen_movsi (const_reg, GEN_INT (-size)));
+             emit_insn (gen_subsi3 (reg, reg, const_reg));
            }
          else
            {
-             rtx reg;
-
-             /* If TEMP is invalid, we could temporarily save a general
-                register to MACL.  However, there is currently no need
-                to handle this case, so just abort when we see it.  */
-             if (temp < 0)
-               abort ();
-             reg = gen_rtx (REG, SImode, temp);
-             emit_insn (gen_movsi (reg, val));
-             val = reg;
+             emit_insn (gen_movsi (const_reg, GEN_INT (size)));
+             emit_insn (gen_addsi3 (reg, reg, const_reg));
            }
        }
-
-      insn = gen_addsi3 (reg, reg, val);
-      emit_insn (insn);
     }
 }