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* fold-const.c (fold): Reorder tests for conditional expressions.
[pf3gnuchains/gcc-fork.git] / gcc / fold-const.c
index 6e17e00..065a4fc 100644 (file)
@@ -5063,6 +5063,14 @@ fold (expr)
                            fold (build1 (code, type, integer_one_node)),
                            fold (build1 (code, type, integer_zero_node))));
    }
+  else if (TREE_CODE_CLASS (code) == '<'
+          && TREE_CODE (arg0) == COMPOUND_EXPR)
+    return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
+                 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
+  else if (TREE_CODE_CLASS (code) == '<'
+          && TREE_CODE (arg1) == COMPOUND_EXPR)
+    return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
+                 fold (build (code, type, arg0, TREE_OPERAND (arg1, 1))));
   else if (TREE_CODE_CLASS (code) == '2'
           || TREE_CODE_CLASS (code) == '<')
     {
@@ -5098,14 +5106,6 @@ fold (expr)
          fold_binary_op_with_conditional_arg (code, type, arg0, arg1,
                                               /*cond_first_p=*/1);
     }
-  else if (TREE_CODE_CLASS (code) == '<'
-          && TREE_CODE (arg0) == COMPOUND_EXPR)
-    return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
-                 fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
-  else if (TREE_CODE_CLASS (code) == '<'
-          && TREE_CODE (arg1) == COMPOUND_EXPR)
-    return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
-                 fold (build (code, type, arg0, TREE_OPERAND (arg1, 1))));
 
   switch (code)
     {
@@ -5849,7 +5849,7 @@ fold (expr)
              && ! contains_placeholder_p (arg0))
            {
              tree arg = save_expr (arg0);
-             return build (PLUS_EXPR, type, arg, arg);
+             return fold (build (PLUS_EXPR, type, arg, arg));
            }
 
          if (flag_unsafe_math_optimizations)
@@ -5857,17 +5857,25 @@ fold (expr)
              enum built_in_function fcode0 = builtin_mathfn_code (arg0);
              enum built_in_function fcode1 = builtin_mathfn_code (arg1);
 
-             /* Optimize sqrt(x)*sqrt(y) as sqrt(x*y).  */
+             /* Optimizations of sqrt(...)*sqrt(...).  */
              if ((fcode0 == BUILT_IN_SQRT && fcode1 == BUILT_IN_SQRT)
                  || (fcode0 == BUILT_IN_SQRTF && fcode1 == BUILT_IN_SQRTF)
                  || (fcode0 == BUILT_IN_SQRTL && fcode1 == BUILT_IN_SQRTL))
                {
-                 tree sqrtfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0);
-                 tree arg = build (MULT_EXPR, type,
-                                   TREE_VALUE (TREE_OPERAND (arg0, 1)),
-                                   TREE_VALUE (TREE_OPERAND (arg1, 1)));
-                 tree arglist = build_tree_list (NULL_TREE, arg);
-                 return fold (build_function_call_expr (sqrtfn, arglist));
+                 tree sqrtfn, arg, arglist;
+                 tree arg00 = TREE_VALUE (TREE_OPERAND (arg0, 1));
+                 tree arg10 = TREE_VALUE (TREE_OPERAND (arg1, 1));
+
+                 /* Optimize sqrt(x)*sqrt(x) as x.  */
+                 if (operand_equal_p (arg00, arg10, 0)
+                     && ! HONOR_SNANS (TYPE_MODE (type)))
+                   return arg00;
+
+                 /* Optimize sqrt(x)*sqrt(y) as sqrt(x*y).  */
+                 sqrtfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0);
+                 arg = fold (build (MULT_EXPR, type, arg00, arg10));
+                 arglist = build_tree_list (NULL_TREE, arg);
+                 return build_function_call_expr (sqrtfn, arglist);
                }
 
              /* Optimize exp(x)*exp(y) as exp(x+y).  */
@@ -5879,8 +5887,43 @@ fold (expr)
                  tree arg = build (PLUS_EXPR, type,
                                    TREE_VALUE (TREE_OPERAND (arg0, 1)),
                                    TREE_VALUE (TREE_OPERAND (arg1, 1)));
-                 tree arglist = build_tree_list (NULL_TREE, arg);
-                 return fold (build_function_call_expr (expfn, arglist));
+                 tree arglist = build_tree_list (NULL_TREE, fold (arg));
+                 return build_function_call_expr (expfn, arglist);
+               }
+
+             /* Optimizations of pow(...)*pow(...).  */
+             if ((fcode0 == BUILT_IN_POW && fcode1 == BUILT_IN_POW)
+                 || (fcode0 == BUILT_IN_POWF && fcode1 == BUILT_IN_POWF)
+                 || (fcode0 == BUILT_IN_POWL && fcode1 == BUILT_IN_POWL))
+               {
+                 tree arg00 = TREE_VALUE (TREE_OPERAND (arg0, 1));
+                 tree arg01 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg0,
+                                                                    1)));
+                 tree arg10 = TREE_VALUE (TREE_OPERAND (arg1, 1));
+                 tree arg11 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg1,
+                                                                    1)));
+
+                 /* Optimize pow(x,y)*pow(z,y) as pow(x*z,y).  */
+                 if (operand_equal_p (arg01, arg11, 0))
+                   {
+                     tree powfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0);
+                     tree arg = build (MULT_EXPR, type, arg00, arg10);
+                     tree arglist = tree_cons (NULL_TREE, fold (arg),
+                                               build_tree_list (NULL_TREE,
+                                                                arg01));
+                     return build_function_call_expr (powfn, arglist);
+                   }
+
+                 /* Optimize pow(x,y)*pow(x,z) as pow(x,y+z).  */
+                 if (operand_equal_p (arg00, arg10, 0))
+                   {
+                     tree powfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0);
+                     tree arg = fold (build (PLUS_EXPR, type, arg01, arg11));
+                     tree arglist = tree_cons (NULL_TREE, arg00,
+                                               build_tree_list (NULL_TREE,
+                                                                arg));
+                     return build_function_call_expr (powfn, arglist);
+                   }
                }
            }
        }
@@ -6052,10 +6095,10 @@ fold (expr)
                              TREE_OPERAND (arg1, 1)));
        }
 
-      /* Optimize x/exp(y) into x*exp(-y).  */
       if (flag_unsafe_math_optimizations)
        {
          enum built_in_function fcode = builtin_mathfn_code (arg1);
+         /* Optimize x/exp(y) into x*exp(-y).  */
          if (fcode == BUILT_IN_EXP
              || fcode == BUILT_IN_EXPF
              || fcode == BUILT_IN_EXPL)
@@ -6063,10 +6106,25 @@ fold (expr)
              tree expfn = TREE_OPERAND (TREE_OPERAND (arg1, 0), 0);
              tree arg = build1 (NEGATE_EXPR, type,
                                 TREE_VALUE (TREE_OPERAND (arg1, 1)));
-             tree arglist = build_tree_list (NULL_TREE, arg);
+             tree arglist = build_tree_list (NULL_TREE, fold (arg));
              arg1 = build_function_call_expr (expfn, arglist);
              return fold (build (MULT_EXPR, type, arg0, arg1));
            }
+
+         /* Optimize x/pow(y,z) into x*pow(y,-z).  */
+         if (fcode == BUILT_IN_POW
+             || fcode == BUILT_IN_POWF
+             || fcode == BUILT_IN_POWL)
+           {
+             tree powfn = TREE_OPERAND (TREE_OPERAND (arg1, 0), 0);
+             tree arg10 = TREE_VALUE (TREE_OPERAND (arg1, 1));
+             tree arg11 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg1, 1)));
+             tree neg11 = fold (build1 (NEGATE_EXPR, type, arg11));
+             tree arglist = tree_cons(NULL_TREE, arg10,
+                                      build_tree_list (NULL_TREE, neg11));
+             arg1 = build_function_call_expr (powfn, arglist);
+             return fold (build (MULT_EXPR, type, arg0, arg1));
+           }
        }
       goto binary;
 
@@ -6426,6 +6484,19 @@ fold (expr)
              && ! TREE_CONSTANT_OVERFLOW (tem))
            return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
 
+         /* Likewise, we can simplify a comparison of a real constant with
+            a MINUS_EXPR whose first operand is also a real constant, i.e.
+            (c1 - x) < c2 becomes x > c1-c2.  */
+         if (flag_unsafe_math_optimizations
+             && TREE_CODE (arg1) == REAL_CST
+             && TREE_CODE (arg0) == MINUS_EXPR
+             && TREE_CODE (TREE_OPERAND (arg0, 0)) == REAL_CST
+             && 0 != (tem = const_binop (MINUS_EXPR, TREE_OPERAND (arg0, 0),
+                                         arg1, 0))
+             && ! TREE_CONSTANT_OVERFLOW (tem))
+           return fold (build (swap_tree_comparison (code), type,
+                               TREE_OPERAND (arg0, 1), tem));
+
          /* Fold comparisons against built-in math functions.  */
          if (TREE_CODE (arg1) == REAL_CST
              && flag_unsafe_math_optimizations