re PR tree-optimization/35202 (exp->expf transformation incorrect with -fmath-errno)

2009-02-09  Richard Guenther  <rguenther@suse.de>

	PR middle-end/35202
	* convert.c (convert_to_real): Disable (float)fn((double)x)
	to fnf(x) conversion if errno differences may occur and
	-fmath-errno is set.

From-SVN: r144030

gcc/ChangeLog

+2009-02-09  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/35202
+	* convert.c (convert_to_real): Disable (float)fn((double)x)
+	to fnf(x) conversion if errno differences may occur and
+	-fmath-errno is set.
+
 2009-02-07  Anatoly Sokolov  <aesok@post.ru>
 
 	* config/avr/avr.c (avr_mcu_t): Add ata6289 device.

gcc/convert.c

@@ -139,40 +139,45 @@ convert_to_real (tree type, tree expr)
       switch (fcode)
         {
 #define CASE_MATHFN(FN) case BUILT_IN_##FN: case BUILT_IN_##FN##L:
-	  CASE_MATHFN (ACOS)
-	  CASE_MATHFN (ACOSH)
-	  CASE_MATHFN (ASIN)
-	  CASE_MATHFN (ASINH)
-	  CASE_MATHFN (ATAN)
-	  CASE_MATHFN (ATANH)
-	  CASE_MATHFN (CBRT)
-	  CASE_MATHFN (COS)
 	  CASE_MATHFN (COSH)
-	  CASE_MATHFN (ERF)
-	  CASE_MATHFN (ERFC)
 	  CASE_MATHFN (EXP)
 	  CASE_MATHFN (EXP10)
 	  CASE_MATHFN (EXP2)
-	  CASE_MATHFN (EXPM1)
-	  CASE_MATHFN (FABS)
+ 	  CASE_MATHFN (EXPM1)
 	  CASE_MATHFN (GAMMA)
 	  CASE_MATHFN (J0)
 	  CASE_MATHFN (J1)
 	  CASE_MATHFN (LGAMMA)
-	  CASE_MATHFN (LOG)
-	  CASE_MATHFN (LOG10)
-	  CASE_MATHFN (LOG1P)
-	  CASE_MATHFN (LOG2)
-	  CASE_MATHFN (LOGB)
 	  CASE_MATHFN (POW10)
-	  CASE_MATHFN (SIN)
 	  CASE_MATHFN (SINH)
-	  CASE_MATHFN (SQRT)
-	  CASE_MATHFN (TAN)
-	  CASE_MATHFN (TANH)
 	  CASE_MATHFN (TGAMMA)
 	  CASE_MATHFN (Y0)
 	  CASE_MATHFN (Y1)
+	    /* The above functions may set errno differently with float
+	       input or output so this transformation is not safe with
+	       -fmath-errno.  */
+	    if (flag_errno_math)
+	      break;
+	  CASE_MATHFN (ACOS)
+	  CASE_MATHFN (ACOSH)
+	  CASE_MATHFN (ASIN)
+ 	  CASE_MATHFN (ASINH)
+ 	  CASE_MATHFN (ATAN)
+	  CASE_MATHFN (ATANH)
+ 	  CASE_MATHFN (CBRT)
+ 	  CASE_MATHFN (COS)
+ 	  CASE_MATHFN (ERF)
+ 	  CASE_MATHFN (ERFC)
+ 	  CASE_MATHFN (FABS)
+	  CASE_MATHFN (LOG)
+	  CASE_MATHFN (LOG10)
+	  CASE_MATHFN (LOG2)
+ 	  CASE_MATHFN (LOG1P)
+ 	  CASE_MATHFN (LOGB)
+ 	  CASE_MATHFN (SIN)
+	  CASE_MATHFN (SQRT)
+ 	  CASE_MATHFN (TAN)
+ 	  CASE_MATHFN (TANH)
 #undef CASE_MATHFN
 	    {
 	      tree arg0 = strip_float_extensions (CALL_EXPR_ARG (expr, 0));