[arm] Make -mfloat-abi=softfp work when there are no

Before this patch series it wasn't really possible to not have an FPU;
it was always there, even if the hardware didn't really support it.
Now that we have -mfpu=auto, the concept of not having an FPU becomes
real.  Consequently, when the -mfloat-abi switch is set to softfp
doing the Right Thing is much more important.  In this case we have a
soft-float ABI, but can use FP instructions if they are available.
To support this we have to separate out TARGET_HARD_FLOAT into two
use cases: one where the instructions exist and one when they don't.
We preserve the original meaning of TARGET_HARD_FLOAT (but add an extra
check) of meaning that we are generating HW FP instructions, and add a
new macro for the special case when use of FP instructions is permitted,
but might not be available at this time (the distinction is important
because they might be enabled by an attribute during the compilation).
TARGET_SOFT_FLOAT continues to be the exact inverse of TARGET_HARD_FLOAT,
but we now define it as such.

	* config/arm/arm.h (TARGET_HARD_FLOAT): Also check that we
	have some floating-point instructions.
	(TARGET_SOFT_FLOAT): Define as inverse of TARGET_HARD_FLOAT.
	(TARGET_MAYBE_HARD_FLOAT): New macro.
	* config/arm/arm-builtins.c (arm_init_builtins): Use
	TARGET_MAYBE_HARD_FLOAT.
	* config/arm/arm.c (arm_option_override): Use TARGET_HARD_FLOAT_ABI.

From-SVN: r249293

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d1abcce666bd5994502e52583a3fe160dd5947a5..c7b1bbb4332de044fee6a9804f911fb6b89f12bd 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2017-06-16  Richard Earnshaw  <rearnsha@arm.com>
+
+       * config/arm/arm.h (TARGET_HARD_FLOAT): Also check that we
+       have some floating-point instructions.
+       (TARGET_SOFT_FLOAT): Define as inverse of TARGET_HARD_FLOAT.
+       (TARGET_MAYBE_HARD_FLOAT): New macro.
+       * config/arm/arm-builtins.c (arm_init_builtins): Use
+       TARGET_MAYBE_HARD_FLOAT.
+       * config/arm/arm.c (arm_option_override): Use TARGET_HARD_FLOAT_ABI.
+
 2017-06-16  Richard Earnshaw  <rearnsha@arm.com>
 
        * common/config/arm/arm-common.c: Define INCLUDE_LIST.

diff --git a/gcc/config/arm/arm-builtins.c b/gcc/config/arm/arm-builtins.c
index 8ecf58171c13c1f02994c1a67acec8a0475de709..8d14e58d916620108f822cbe88a5c377e3535296 100644 (file)
--- a/gcc/config/arm/arm-builtins.c
+++ b/gcc/config/arm/arm-builtins.c
@@ -1876,7 +1876,7 @@ arm_init_builtins (void)
      arm_init_neon_builtins which uses it.  */
   arm_init_fp16_builtins ();
 
-  if (TARGET_HARD_FLOAT)
+  if (TARGET_MAYBE_HARD_FLOAT)
     {
       arm_init_neon_builtins ();
       arm_init_vfp_builtins ();
@@ -1885,7 +1885,7 @@ arm_init_builtins (void)
 
   arm_init_acle_builtins ();
 
-  if (TARGET_HARD_FLOAT)
+  if (TARGET_MAYBE_HARD_FLOAT)
     {
       tree ftype_set_fpscr
        = build_function_type_list (void_type_node, unsigned_type_node, NULL);

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 9e857a2b011d89b21c98bda7a3cfefd0d7664d7b..385792ddc4db9689d375d9a24f53f915ec6d8c7f 100644 (file)
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -3449,8 +3449,7 @@ arm_option_override (void)
     {
       if (arm_abi == ARM_ABI_IWMMXT)
        arm_pcs_default = ARM_PCS_AAPCS_IWMMXT;
-      else if (arm_float_abi == ARM_FLOAT_ABI_HARD
-              && TARGET_HARD_FLOAT)
+      else if (TARGET_HARD_FLOAT_ABI)
        {
          arm_pcs_default = ARM_PCS_AAPCS_VFP;
          if (!bitmap_bit_p (arm_active_target.isa, isa_bit_VFPv2))

diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 57f4958e2b5dae0d06ff9e8e307b345a91a70549..92361fc9c30ed358a03fb42c332bd8293431aae1 100644 (file)
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -119,9 +119,14 @@ extern tree arm_fp16_type_node;
 #define TARGET_32BIT_P(flags)  (TARGET_ARM_P (flags) || TARGET_THUMB2_P (flags))
 
 /* Run-time Target Specification.  */
-#define TARGET_SOFT_FLOAT              (arm_float_abi == ARM_FLOAT_ABI_SOFT)
 /* Use hardware floating point instructions. */
-#define TARGET_HARD_FLOAT              (arm_float_abi != ARM_FLOAT_ABI_SOFT)
+#define TARGET_HARD_FLOAT      (arm_float_abi != ARM_FLOAT_ABI_SOFT    \
+                                && bitmap_bit_p (arm_active_target.isa, \
+                                                 isa_bit_VFPv2))
+#define TARGET_SOFT_FLOAT      (!TARGET_HARD_FLOAT)
+/* User has permitted use of FP instructions, if they exist for this
+   target.  */
+#define TARGET_MAYBE_HARD_FLOAT (arm_float_abi != ARM_FLOAT_ABI_SOFT)
 /* Use hardware floating point calling convention.  */
 #define TARGET_HARD_FLOAT_ABI          (arm_float_abi == ARM_FLOAT_ABI_HARD)
 #define TARGET_IWMMXT                  (arm_arch_iwmmxt)