recog: Fix propagation into ASM_OPERANDS

An inline asm with multiple output operands is represented as a
parallel set in which the SET_SRCs are the same (shared) ASM_OPERANDS.
insn_propagation didn't account for this, and instead propagated
into each ASM_OPERANDS individually.  This meant that it could
apply a substitution X->Y to Y itself, which (a) could create
circularity and (b) would be semantically wrong in any case,
since Y might use a different value of X.

This patch checks explicitly for parallels involving ASM_OPERANDS,
just like combine does.

gcc/
	* recog.cc (insn_propagation::apply_to_pattern_1): Handle shared
	ASM_OPERANDS.

diff --git a/gcc/recog.cc b/gcc/recog.cc
index e12b4c9500e3323ceb5675d9aa4263573b0b6a18..3bd2d73c25909b10b1f27cc2e7e0f3ac9a8983ae 100644 (file)
--- a/gcc/recog.cc
+++ b/gcc/recog.cc
@@ -1339,13 +1339,26 @@ insn_propagation::apply_to_pattern_1 (rtx *loc)
              && apply_to_pattern_1 (&COND_EXEC_CODE (body)));
 
     case PARALLEL:
-      {
-       int last = XVECLEN (body, 0) - 1;
-       for (int i = 0; i < last; ++i)
-         if (!apply_to_pattern_1 (&XVECEXP (body, 0, i)))
-           return false;
-       return apply_to_pattern_1 (&XVECEXP (body, 0, last));
-      }
+      for (int i = 0; i < XVECLEN (body, 0); ++i)
+       {
+         rtx *subloc = &XVECEXP (body, 0, i);
+         if (GET_CODE (*subloc) == SET)
+           {
+             if (!apply_to_lvalue_1 (SET_DEST (*subloc)))
+               return false;
+             /* ASM_OPERANDS are shared between SETs in the same PARALLEL.
+                Only process them on the first iteration.  */
+             if ((i == 0 || GET_CODE (SET_SRC (*subloc)) != ASM_OPERANDS)
+                 && !apply_to_rvalue_1 (&SET_SRC (*subloc)))
+               return false;
+           }
+         else
+           {
+             if (!apply_to_pattern_1 (subloc))
+               return false;
+           }
+       }
+      return true;
 
     case ASM_OPERANDS:
       for (int i = 0, len = ASM_OPERANDS_INPUT_LENGTH (body); i < len; ++i)