re PR middle-end/323 (optimized code gives strange floating point results)

	PR rtl-optimization/323
	* c-common.c (c_fully_fold, convert_and_check,
	c_common_truthvalue_conversion): Handle EXCESS_PRECISION_EXPR.
	(c_fully_fold_internal): Disallow EXCESS_PRECISION_EXPR.
	* c-common.def (EXCESS_PRECISION_EXPR): New.
	* c-cppbuiltin.c (builtin_define_float_constants): Define
	constants with enough digits for long double.
	* c-lex.c (interpret_float): Interpret constant with excess
	precision where appropriate.
	* c-opts.c (c_common_post_options): Set
	flag_excess_precision_cmdline.  Give an error for
	-fexcess-precision=standard for C++ for processors where the
	option is significant.
	* c-parser.c (c_parser_conditional_expression): Handle excess
	precision in condition.
	* c-typeck.c (convert_arguments): Handle arguments with excess
	precision.
	(build_unary_op): Move excess precision outside operation.
	(build_conditional_expr): Likewise.
	(build_compound_expr): Likewise.
	(build_c_cast): Do cast on operand of EXCESS_PRECISION_EXPR.
	(build_modify_expr): Handle excess precision in RHS.
	(convert_for_assignment): Handle excess precision in converted
	value.
	(digest_init, output_init_element, process_init_element): Handle
	excess precision in initializer.
	(c_finish_return): Handle excess precision in return value.
	(build_binary_op): Handle excess precision in operands and add
	excess precision as needed for operation.
	* common.opt (-fexcess-precision=): New option.
	* config/i386/i386.h (X87_ENABLE_ARITH, X87_ENABLE_FLOAT): New.
	* config/i386/i386.md (float<SSEMODEI24:mode><X87MODEF:mode>2):
	For standard excess precision, output explicit conversion to and
	truncation from XFmode.
	(*float<SSEMODEI24:mode><X87MODEF:mode>2_1,
	*float<SSEMODEI24:mode><X87MODEF:mode>2_i387_with_temp,
	*float<SSEMODEI24:mode><X87MODEF:mode>2_i387, two unnamed
	define_splits, floatdi<X87MODEF:mode>2_i387_with_xmm, two unnamed
	define_splits, *floatunssi<mode>2_1, two unnamed define_splits,
	floatunssi<mode>2, add<mode>3, sub<mode>3, mul<mode>3, divdf3,
	divsf3, *fop_<mode>_comm_i387, *fop_<mode>_1_i387,
	*fop_<MODEF:mode>_2_i387, *fop_<MODEF:mode>_3_i387,
	*fop_df_4_i387, *fop_df_5_i387, *fop_df_6_i387, two unnamed
	define_splits, sqrt<mode>2): Disable where appropriate for
	standard excess precision.
	* convert.c (convert_to_real): Do not shorten arithmetic to type
	for which excess precision would be used.
	* defaults.h (TARGET_FLT_EVAL_METHOD_NON_DEFAULT): Define.
	* doc/invoke.texi (-fexcess-precision=): Document option.
	(-mfpmath=): Correct index entry.
	* flags.h (enum excess_precision, flag_excess_precision_cmdline,
	flag_excess_precision): New.
	* langhooks.c (lhd_post_options): Set
	flag_excess_precision_cmdline.
	* opts.c (common_handle_option): Handle -fexcess-precision=.
	* toplev.c (flag_excess_precision_cmdline, flag_excess_precision,
	init_excess_precision): New.
	(lang_dependent_init_target): Call init_excess_precision.
	* tree.c (excess_precision_type): New.
	* tree.h (excess_precision_type): Declare.

ada:
	* gcc-interface/misc.c (gnat_post_options): Set
	flag_excess_precision_cmdline.  Give an error for
	-fexcess-precision=standard for processors where the option is
	significant.

fortran:
	* options.c (gfc_post_options): Set
	flag_excess_precision_cmdline.  Give an error for
	-fexcess-precision=standard for processors where the option is
	significant.

java:
	* lang.c (java_post_options): Set flag_excess_precision_cmdline.
	Give an error for -fexcess-precision=standard for processors where
	the option is significant.

testsuite:
	* gcc.target/i386/excess-precision-1.c,
	gcc.target/i386/excess-precision-2.c,
	gcc.target/i386/excess-precision-3.c,
	gcc.target/i386/excess-precision-4.c,
	gcc.target/i386/excess-precision-5.c,
	gcc.target/i386/excess-precision-6.c: New tests.

From-SVN: r145272

2 files changed, 78 insertions, 25 deletions

diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
index e4d4463..89e26f6 100644
--- a/gcc/config/i386/i386.h
+++ b/gcc/config/i386/i386.h
@@ -611,6 +611,20 @@ enum target_cpu_default
 #define TARGET_FLT_EVAL_METHOD \
   (TARGET_MIX_SSE_I387 ? -1 : TARGET_SSE_MATH ? 0 : 2)
 
+/* Whether to allow x87 floating-point arithmetic on MODE (one of
+   SFmode, DFmode and XFmode) in the current excess precision
+   configuration.  */
+#define X87_ENABLE_ARITH(MODE) \
+  (flag_excess_precision == EXCESS_PRECISION_FAST || (MODE) == XFmode)
+
+/* Likewise, whether to allow direct conversions from integer mode
+   IMODE (HImode, SImode or DImode) to MODE.  */
+#define X87_ENABLE_FLOAT(MODE, IMODE)			\
+  (flag_excess_precision == EXCESS_PRECISION_FAST	\
+   || (MODE) == XFmode					\
+   || ((MODE) == DFmode && (IMODE) == SImode)		\
+   || (IMODE) == HImode)
+
 /* target machine storage layout */
 
 #define SHORT_TYPE_SIZE 16
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index a112198..9592f91 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -5137,13 +5137,28 @@
   "TARGET_80387
    || ((<SSEMODEI24:MODE>mode != DImode || TARGET_64BIT)
        && SSE_FLOAT_MODE_P (<X87MODEF:MODE>mode) && TARGET_SSE_MATH)"
-  "")
+  "
+{
+  if (!((<SSEMODEI24:MODE>mode != DImode || TARGET_64BIT)
+	&& SSE_FLOAT_MODE_P (<X87MODEF:MODE>mode) && TARGET_SSE_MATH)
+      && !X87_ENABLE_FLOAT (<X87MODEF:MODE>mode, <SSEMODEI24:MODE>mode))
+    {
+      rtx reg = gen_reg_rtx (XFmode);
+      emit_insn (gen_float<SSEMODEI24:mode>xf2 (reg, operands[1]));
+/* Avoid references to nonexistent function in dead code in XFmode case.  */
+#define gen_truncxfxf2 gen_truncxfdf2
+      emit_insn (gen_truncxf<X87MODEF:mode>2 (operands[0], reg));
+#undef gen_truncxfxf2
+      DONE;
+    }
+}")
 
 ;; Pre-reload splitter to add memory clobber to the pattern.
 (define_insn_and_split "*float<SSEMODEI24:mode><X87MODEF:mode>2_1"
   [(set (match_operand:X87MODEF 0 "register_operand" "")
 	(float:X87MODEF (match_operand:SSEMODEI24 1 "register_operand" "")))]
   "((TARGET_80387
+     && X87_ENABLE_FLOAT (<X87MODEF:MODE>mode, <SSEMODEI24:MODE>mode)
      && (!((<SSEMODEI24:MODE>mode != DImode || TARGET_64BIT)
 	   && SSE_FLOAT_MODE_P (<X87MODEF:MODE>mode) && TARGET_SSE_MATH)
 	 || TARGET_MIX_SSE_I387))
@@ -5524,7 +5539,8 @@
 	(float:X87MODEF
 	  (match_operand:SSEMODEI24 1 "nonimmediate_operand" "m,?r")))
   (clobber (match_operand:SSEMODEI24 2 "memory_operand" "=X,m"))]
-  "TARGET_80387"
+  "TARGET_80387
+   && X87_ENABLE_FLOAT (<X87MODEF:MODE>mode, <SSEMODEI24:MODE>mode)"
   "@
    fild%z1\t%1
    #"
@@ -5537,7 +5553,8 @@
   [(set (match_operand:X87MODEF 0 "register_operand" "=f")
 	(float:X87MODEF
 	  (match_operand:SSEMODEI24 1 "memory_operand" "m")))]
-  "TARGET_80387"
+  "TARGET_80387
+   && X87_ENABLE_FLOAT (<X87MODEF:MODE>mode, <SSEMODEI24:MODE>mode)"
   "fild%z1\t%1"
   [(set_attr "type" "fmov")
    (set_attr "mode" "<X87MODEF:MODE>")
@@ -5548,6 +5565,7 @@
 	(float:X87MODEF (match_operand:SSEMODEI24 1 "register_operand" "")))
    (clobber (match_operand:SSEMODEI24 2 "memory_operand" ""))]
   "TARGET_80387
+   && X87_ENABLE_FLOAT (<X87MODEF:MODE>mode, <SSEMODEI24:MODE>mode)
    && reload_completed
    && FP_REG_P (operands[0])"
   [(set (match_dup 2) (match_dup 1))
@@ -5559,6 +5577,7 @@
 	(float:X87MODEF (match_operand:SSEMODEI24 1 "memory_operand" "")))
    (clobber (match_operand:SSEMODEI24 2 "memory_operand" ""))]
   "TARGET_80387
+   && X87_ENABLE_FLOAT (<X87MODEF:MODE>mode, <SSEMODEI24:MODE>mode)
    && reload_completed
    && FP_REG_P (operands[0])"
   [(set (match_dup 0) (float:X87MODEF (match_dup 1)))]
@@ -5574,7 +5593,8 @@
    (clobber (match_scratch:V4SI 3 "=X,x"))
    (clobber (match_scratch:V4SI 4 "=X,x"))
    (clobber (match_operand:DI 2 "memory_operand" "=X,m"))]
-  "TARGET_80387 && TARGET_SSE2 && TARGET_INTER_UNIT_MOVES
+  "TARGET_80387 && X87_ENABLE_FLOAT (<X87MODEF:MODE>mode, DImode)
+   && TARGET_SSE2 && TARGET_INTER_UNIT_MOVES
    && !TARGET_64BIT && optimize_function_for_speed_p (cfun)"
   "#"
   [(set_attr "type" "multi")
@@ -5588,7 +5608,8 @@
    (clobber (match_scratch:V4SI 3 ""))
    (clobber (match_scratch:V4SI 4 ""))
    (clobber (match_operand:DI 2 "memory_operand" ""))]
-  "TARGET_80387 && TARGET_SSE2 && TARGET_INTER_UNIT_MOVES
+  "TARGET_80387 && X87_ENABLE_FLOAT (<X87MODEF:MODE>mode, DImode)
+   && TARGET_SSE2 && TARGET_INTER_UNIT_MOVES
    && !TARGET_64BIT && optimize_function_for_speed_p (cfun)
    && reload_completed
    && FP_REG_P (operands[0])"
@@ -5612,7 +5633,8 @@
    (clobber (match_scratch:V4SI 3 ""))
    (clobber (match_scratch:V4SI 4 ""))
    (clobber (match_operand:DI 2 "memory_operand" ""))]
-  "TARGET_80387 && TARGET_SSE2 && TARGET_INTER_UNIT_MOVES
+  "TARGET_80387 && X87_ENABLE_FLOAT (<X87MODEF:MODE>mode, DImode)
+   && TARGET_SSE2 && TARGET_INTER_UNIT_MOVES
    && !TARGET_64BIT && optimize_function_for_speed_p (cfun)
    && reload_completed
    && FP_REG_P (operands[0])"
@@ -5632,7 +5654,8 @@
    (clobber (match_operand:DI 2 "memory_operand" "=m,m"))
    (clobber (match_scratch:SI 3 "=X,x"))]
   "!TARGET_64BIT
-   && TARGET_80387 && TARGET_SSE"
+   && TARGET_80387 && X87_ENABLE_FLOAT (<X87MODEF:MODE>mode, SImode)
+   && TARGET_SSE"
   "#"
   [(set_attr "type" "multi")
    (set_attr "mode" "<MODE>")])
@@ -5644,7 +5667,8 @@
    (clobber (match_operand:DI 2 "memory_operand" ""))
    (clobber (match_scratch:SI 3 ""))]
   "!TARGET_64BIT
-   && TARGET_80387 && TARGET_SSE
+   && TARGET_80387 && X87_ENABLE_FLOAT (<X87MODEF:MODE>mode, SImode)
+   && TARGET_SSE
    && reload_completed"
   [(set (match_dup 2) (match_dup 1))
    (set (match_dup 0)
@@ -5658,7 +5682,8 @@
    (clobber (match_operand:DI 2 "memory_operand" ""))
    (clobber (match_scratch:SI 3 ""))]
   "!TARGET_64BIT
-   && TARGET_80387 && TARGET_SSE
+   && TARGET_80387 && X87_ENABLE_FLOAT (<X87MODEF:MODE>mode, SImode)
+   && TARGET_SSE
    && reload_completed"
   [(set (match_dup 2) (match_dup 3))
    (set (match_dup 0)
@@ -5676,7 +5701,8 @@
       (clobber (match_dup 2))
       (clobber (match_scratch:SI 3 ""))])]
   "!TARGET_64BIT
-   && ((TARGET_80387 && TARGET_SSE)
+   && ((TARGET_80387 && X87_ENABLE_FLOAT (<X87MODEF:MODE>mode, SImode)
+	&& TARGET_SSE)
        || (SSE_FLOAT_MODE_P (<MODE>mode) && TARGET_SSE_MATH))"
 {
   if (SSE_FLOAT_MODE_P (<MODE>mode) && TARGET_SSE_MATH)
@@ -7475,7 +7501,8 @@
   [(set (match_operand:MODEF 0 "register_operand" "")
 	(plus:MODEF (match_operand:MODEF 1 "register_operand" "")
 		    (match_operand:MODEF 2 "nonimmediate_operand" "")))]
-  "TARGET_80387 || (SSE_FLOAT_MODE_P (<MODE>mode) && TARGET_SSE_MATH)"
+  "(TARGET_80387 && X87_ENABLE_ARITH (<MODE>mode))
+    || (SSE_FLOAT_MODE_P (<MODE>mode) && TARGET_SSE_MATH)"
   "")
 
 ;; Subtract instructions
@@ -7835,7 +7862,8 @@
   [(set (match_operand:MODEF 0 "register_operand" "")
 	(minus:MODEF (match_operand:MODEF 1 "register_operand" "")
 		     (match_operand:MODEF 2 "nonimmediate_operand" "")))]
-  "TARGET_80387 || (SSE_FLOAT_MODE_P (<MODE>mode) && TARGET_SSE_MATH)"
+  "(TARGET_80387 && X87_ENABLE_ARITH (<MODE>mode))
+    || (SSE_FLOAT_MODE_P (<MODE>mode) && TARGET_SSE_MATH)"
   "")
 
 ;; Multiply instructions
@@ -8390,7 +8418,8 @@
   [(set (match_operand:MODEF 0 "register_operand" "")
 	(mult:MODEF (match_operand:MODEF 1 "register_operand" "")
 		    (match_operand:MODEF 2 "nonimmediate_operand" "")))]
-  "TARGET_80387 || (SSE_FLOAT_MODE_P (<MODE>mode) && TARGET_SSE_MATH)"
+  "(TARGET_80387 && X87_ENABLE_ARITH (<MODE>mode))
+    || (SSE_FLOAT_MODE_P (<MODE>mode) && TARGET_SSE_MATH)"
   "")
 
 ;; SSE5 scalar multiply/add instructions are defined in sse.md.
@@ -8431,14 +8460,16 @@
   [(set (match_operand:DF 0 "register_operand" "")
  	(div:DF (match_operand:DF 1 "register_operand" "")
  		(match_operand:DF 2 "nonimmediate_operand" "")))]
-   "TARGET_80387 || (TARGET_SSE2 && TARGET_SSE_MATH)"
+   "(TARGET_80387 && X87_ENABLE_ARITH (DFmode))
+    || (TARGET_SSE2 && TARGET_SSE_MATH)"
    "")
 
 (define_expand "divsf3"
   [(set (match_operand:SF 0 "register_operand" "")
 	(div:SF (match_operand:SF 1 "register_operand" "")
 		(match_operand:SF 2 "nonimmediate_operand" "")))]
-  "TARGET_80387 || TARGET_SSE_MATH"
+  "(TARGET_80387 && X87_ENABLE_ARITH (SFmode))
+    || TARGET_SSE_MATH"
 {
   if (TARGET_SSE_MATH && TARGET_RECIP && optimize_insn_for_speed_p ()
       && flag_finite_math_only && !flag_trapping_math
@@ -16317,7 +16348,7 @@
 	(match_operator:MODEF 3 "binary_fp_operator"
 	  [(match_operand:MODEF 1 "nonimmediate_operand" "%0")
 	   (match_operand:MODEF 2 "nonimmediate_operand" "fm")]))]
-  "TARGET_80387
+  "TARGET_80387 && X87_ENABLE_ARITH (<MODE>mode)
    && COMMUTATIVE_ARITH_P (operands[3])
    && !(MEM_P (operands[1]) && MEM_P (operands[2]))"
   "* return output_387_binary_op (insn, operands);"
@@ -16431,7 +16462,8 @@
 	(match_operator:MODEF 3 "binary_fp_operator"
 	  [(match_operand:MODEF 1 "nonimmediate_operand" "0,fm")
 	   (match_operand:MODEF 2 "nonimmediate_operand" "fm,0")]))]
-  "TARGET_80387 && !(SSE_FLOAT_MODE_P (<MODE>mode) && TARGET_SSE_MATH)
+  "TARGET_80387 && X87_ENABLE_ARITH (<MODE>mode)
+   && !(SSE_FLOAT_MODE_P (<MODE>mode) && TARGET_SSE_MATH)
    && !COMMUTATIVE_ARITH_P (operands[3])
    && !(MEM_P (operands[1]) && MEM_P (operands[2]))"
   "* return output_387_binary_op (insn, operands);"
@@ -16451,7 +16483,8 @@
 	  [(float:MODEF
 	     (match_operand:X87MODEI12 1 "nonimmediate_operand" "m,?r"))
 	   (match_operand:MODEF 2 "register_operand" "0,0")]))]
-  "TARGET_80387 && !(SSE_FLOAT_MODE_P (<MODEF:MODE>mode) && TARGET_SSE_MATH)
+  "TARGET_80387 && X87_ENABLE_FLOAT (<MODEF:MODE>mode, <X87MODEI12:MODE>mode)
+   && !(SSE_FLOAT_MODE_P (<MODEF:MODE>mode) && TARGET_SSE_MATH)
    && (TARGET_USE_<X87MODEI12:MODE>MODE_FIOP || optimize_function_for_size_p (cfun))"
   "* return which_alternative ? \"#\" : output_387_binary_op (insn, operands);"
   [(set (attr "type")
@@ -16470,7 +16503,8 @@
 	  [(match_operand:MODEF 1 "register_operand" "0,0")
 	   (float:MODEF
 	     (match_operand:X87MODEI12 2 "nonimmediate_operand" "m,?r"))]))]
-  "TARGET_80387 && !(SSE_FLOAT_MODE_P (<MODEF:MODE>mode) && TARGET_SSE_MATH)
+  "TARGET_80387 && X87_ENABLE_FLOAT (<MODEF:MODE>mode, <X87MODEI12:MODE>mode)
+   && !(SSE_FLOAT_MODE_P (<MODEF:MODE>mode) && TARGET_SSE_MATH)
    && (TARGET_USE_<X87MODEI12:MODE>MODE_FIOP || optimize_function_for_size_p (cfun))"
   "* return which_alternative ? \"#\" : output_387_binary_op (insn, operands);"
   [(set (attr "type")
@@ -16489,7 +16523,8 @@
 	   [(float_extend:DF
 	     (match_operand:SF 1 "nonimmediate_operand" "fm,0"))
 	    (match_operand:DF 2 "register_operand" "0,f")]))]
-  "TARGET_80387 && !(TARGET_SSE2 && TARGET_SSE_MATH)
+  "TARGET_80387 && X87_ENABLE_ARITH (DFmode)
+   && !(TARGET_SSE2 && TARGET_SSE_MATH)
    && !(MEM_P (operands[1]) && MEM_P (operands[2]))"
   "* return output_387_binary_op (insn, operands);"
   [(set (attr "type")
@@ -16507,7 +16542,8 @@
 	  [(match_operand:DF 1 "register_operand" "0,f")
 	   (float_extend:DF
 	    (match_operand:SF 2 "nonimmediate_operand" "fm,0"))]))]
-  "TARGET_80387 && !(TARGET_SSE2 && TARGET_SSE_MATH)"
+  "TARGET_80387 && X87_ENABLE_ARITH (DFmode)
+   && !(TARGET_SSE2 && TARGET_SSE_MATH)"
   "* return output_387_binary_op (insn, operands);"
   [(set (attr "type")
         (cond [(match_operand:DF 3 "mult_operator" "")
@@ -16525,7 +16561,8 @@
 	    (match_operand:SF 1 "register_operand" "0,f"))
 	   (float_extend:DF
 	    (match_operand:SF 2 "nonimmediate_operand" "fm,0"))]))]
-  "TARGET_80387 && !(TARGET_SSE2 && TARGET_SSE_MATH)"
+  "TARGET_80387 && X87_ENABLE_ARITH (DFmode)
+   && !(TARGET_SSE2 && TARGET_SSE_MATH)"
   "* return output_387_binary_op (insn, operands);"
   [(set (attr "type")
         (cond [(match_operand:DF 3 "mult_operator" "")
@@ -16661,7 +16698,8 @@
 	   [(float (match_operand:X87MODEI12 1 "register_operand" ""))
 	    (match_operand 2 "register_operand" "")]))]
   "reload_completed
-   && X87_FLOAT_MODE_P (GET_MODE (operands[0]))"
+   && X87_FLOAT_MODE_P (GET_MODE (operands[0]))
+   && X87_ENABLE_FLOAT (GET_MODE (operands[0]), GET_MODE (operands[1]))"
   [(const_int 0)]
 {
   operands[4] = ix86_force_to_memory (GET_MODE (operands[1]), operands[1]);
@@ -16681,7 +16719,8 @@
 	   [(match_operand 1 "register_operand" "")
 	    (float (match_operand:X87MODEI12 2 "register_operand" ""))]))]
   "reload_completed
-   && X87_FLOAT_MODE_P (GET_MODE (operands[0]))"
+   && X87_FLOAT_MODE_P (GET_MODE (operands[0]))
+   && X87_ENABLE_FLOAT (GET_MODE (operands[0]), GET_MODE (operands[2]))"
   [(const_int 0)]
 {
   operands[4] = ix86_force_to_memory (GET_MODE (operands[2]), operands[2]);
@@ -16767,7 +16806,7 @@
   [(set (match_operand:MODEF 0 "register_operand" "")
 	(sqrt:MODEF
 	  (match_operand:MODEF 1 "nonimmediate_operand" "")))]
-  "TARGET_USE_FANCY_MATH_387
+  "(TARGET_USE_FANCY_MATH_387 && X87_ENABLE_ARITH (<MODE>mode))
    || (SSE_FLOAT_MODE_P (<MODE>mode) && TARGET_SSE_MATH)"
 {
   if (<MODE>mode == SFmode