[ARM] Fix pr39501

[Richard Earnshaw <Richard dot Earnshaw at buzzard dot freeserve dot co dot uk>]

I suspect that there may be an underlying mid-end problem behind this
bug, but this patch fixes the problem here by disabling a pattern when
TARGET_HARD_FLOAT is not defined.  In that situation, the MIN_EXPR and
MAX_EXPR nodes are generated for float-point ?: operations (since we
don't have to worry about NaNs).  When these nodes are expanded, the
mid-end code seems to fail to take into account that the soft-float
comparison operations are allowed to return a bool rather than -ve,0,+ve
provided that FLOAT_LIB_COMPARE_RETURNS_BOOL is also defined.

I'll take a look into the mid-end problem shortly, when I have a bit
more spare time; but I need a patch that can safely be back-ported to
earlier branches (since this is a serious silent wrong-code bug) and
fixing the mid-end problem looks quite invasive.

tested on arm-none-eabi.

2009-04-04  Richard Earnshaw  <rearnsha@arm.com>

	PR target/39501
	* arm.md (movsfcc): Disable if not TARGET_HARD_FLOAT.
	* testsuite/gcc.c-torture/execute/pr39501.c: New file.
	* testsuite/gcc.c-torture/execute/pr39501.x: New file.

*** config/arm/arm.md	(revision 145570)
--- config/arm/arm.md	(local)
*************** (define_expand "movsfcc"
*** 8260,8266 ****
  	(if_then_else:SF (match_operand 1 "arm_comparison_operator" "")
  			 (match_operand:SF 2 "s_register_operand" "")
  			 (match_operand:SF 3 "nonmemory_operand" "")))]
!   "TARGET_32BIT"
    "
    {
      enum rtx_code code = GET_CODE (operands[1]);
--- 8260,8266 ----
  	(if_then_else:SF (match_operand 1 "arm_comparison_operator" "")
  			 (match_operand:SF 2 "s_register_operand" "")
  			 (match_operand:SF 3 "nonmemory_operand" "")))]
!   "TARGET_32BIT && TARGET_HARD_FLOAT"
    "
    {
      enum rtx_code code = GET_CODE (operands[1]);
*** testsuite/gcc.c-torture/execute/pr39501.c	(revision 145570)
--- testsuite/gcc.c-torture/execute/pr39501.c	(local)
***************
*** 0 ****
--- 1,83 ----
+ /* { dg-options "-ffast-math" } */
+ #define min1(a,b) ((a) < (b) ? (a) : (b))
+ #define max1(a,b) ((a) > (b) ? (a) : (b))
+ 
+ #define min2(a,b) ((a) <= (b) ? (a) : (b))
+ #define max2(a,b) ((a) >= (b) ? (a) : (b))
+ 
+ #define F(type,n)						\
+   type __attribute__((noinline)) type##_##n(type a, type b)	\
+   {								\
+     return n(a, b);						\
+   }
+ 
+ F(float,min1)
+ F(float,min2)
+ F(float,max1)
+ F(float,max2)
+ 
+ F(double,min1)
+ F(double,min2)
+ F(double,max1)
+ F(double,max2)
+ 
+ int main()
+ {
+   if (float_min1(0.f, -1.f) != -1.f) abort();
+   if (float_min1(-1.f, 0.f) != -1.f) abort();
+   if (float_min1(0.f, 1.f)  != 0.f)  abort();
+   if (float_min1(1.f, 0.f)  != 0.f)  abort();
+   if (float_min1(-1.f, 1.f) != -1.f) abort();
+   if (float_min1(1.f, -1.f) != -1.f) abort();
+   
+   if (float_max1(0.f, -1.f) != 0.f)  abort();
+   if (float_max1(-1.f, 0.f) != 0.f)  abort();
+   if (float_max1(0.f, 1.f)  != 1.f)  abort();
+   if (float_max1(1.f, 0.f)  != 1.f)  abort();
+   if (float_max1(-1.f, 1.f) != 1.f)  abort();
+   if (float_max1(1.f, -1.f) != 1.f)  abort();
+   
+   if (float_min2(0.f, -1.f) != -1.f) abort();
+   if (float_min2(-1.f, 0.f) != -1.f) abort();
+   if (float_min2(0.f, 1.f)  != 0.f)  abort();
+   if (float_min2(1.f, 0.f)  != 0.f)  abort();
+   if (float_min2(-1.f, 1.f) != -1.f) abort();
+   if (float_min2(1.f, -1.f) != -1.f) abort();
+   
+   if (float_max2(0.f, -1.f) != 0.f)  abort();
+   if (float_max2(-1.f, 0.f) != 0.f)  abort();
+   if (float_max2(0.f, 1.f)  != 1.f)  abort();
+   if (float_max2(1.f, 0.f)  != 1.f)  abort();
+   if (float_max2(-1.f, 1.f) != 1.f)  abort();
+   if (float_max2(1.f, -1.f) != 1.f)  abort();
+   
+   if (double_min1(0., -1.) != -1.) abort();
+   if (double_min1(-1., 0.) != -1.) abort();
+   if (double_min1(0., 1.)  != 0.)  abort();
+   if (double_min1(1., 0.)  != 0.)  abort();
+   if (double_min1(-1., 1.) != -1.) abort();
+   if (double_min1(1., -1.) != -1.) abort();
+   
+   if (double_max1(0., -1.) != 0.)  abort();
+   if (double_max1(-1., 0.) != 0.)  abort();
+   if (double_max1(0., 1.)  != 1.)  abort();
+   if (double_max1(1., 0.)  != 1.)  abort();
+   if (double_max1(-1., 1.) != 1.)  abort();
+   if (double_max1(1., -1.) != 1.)  abort();
+   
+   if (double_min2(0., -1.) != -1.) abort();
+   if (double_min2(-1., 0.) != -1.) abort();
+   if (double_min2(0., 1.)  != 0.)  abort();
+   if (double_min2(1., 0.)  != 0.)  abort();
+   if (double_min2(-1., 1.) != -1.) abort();
+   if (double_min2(1., -1.) != -1.) abort();
+   
+   if (double_max2(0., -1.) != 0.)  abort();
+   if (double_max2(-1., 0.) != 0.)  abort();
+   if (double_max2(0., 1.)  != 1.)  abort();
+   if (double_max2(1., 0.)  != 1.)  abort();
+   if (double_max2(-1., 1.) != 1.)  abort();
+   if (double_max2(1., -1.) != 1.)  abort();
+   
+   exit(0);
+ }
*** testsuite/gcc.c-torture/execute/pr39501.x	(revision 145570)
--- testsuite/gcc.c-torture/execute/pr39501.x	(local)
***************
*** 0 ****
--- 1,2 ----
+ set additional_flags "-ffast-math"
+ return 0