Revise -mdisable-fpregs option and add new -msoft-mult option

The behavior of the -mdisable-fpregs is confusing in that it doesn't
disable the use of the floating-point registers in all situations.
The -msoft-float disables the use of the floating-point registers in
all situations.  The Linux kernel only needs to disable use of the
xmpyu instruction to avoid using the floating-point registers.

This change revises the -mdisable-fpregs option to disable the use of
the floating-point registers in all situations.  It is now equivalent
to the -msoft-float option.  A new -msoft-mult option is added to
disable use of the xmpyu instruction.  The libgcc library can be
compiled with the -msoft-mult option to avoid using hardware integer
multiplication.

2021-10-24  John David Anglin  <danglin@gcc.gnu.org>

gcc/ChangeLog:

	* config/pa/pa-d.c (pa_d_handle_target_float_abi): Don't check
	TARGET_DISABLE_FPREGS.
	* config/pa/pa.c (fix_range): Use MASK_SOFT_FLOAT instead of
	MASK_DISABLE_FPREGS.
	(hppa_rtx_costs): Don't check TARGET_DISABLE_FPREGS.  Adjust
	cost of hardware integer multiplication.
	(pa_conditional_register_usage): Don't check TARGET_DISABLE_FPREGS.
	* config/pa/pa.h (INT14_OK_STRICT): Likewise.
	* config/pa/pa.md: Don't check TARGET_DISABLE_FPREGS. Check
	TARGET_SOFT_FLOAT in patterns that use xmpyu instruction.
	* config/pa/pa.opt (mdisable-fpregs): Change target mask to
	SOFT_FLOAT.  Revise comment.
	(msoft-float): New option.

5 files changed, 23 insertions, 20 deletions

diff --git a/gcc/config/pa/pa-d.c b/gcc/config/pa/pa-d.c
index 6802738..14ef8ca 100644
--- a/gcc/config/pa/pa-d.c
+++ b/gcc/config/pa/pa-d.c
@@ -47,7 +47,7 @@ pa_d_handle_target_float_abi (void)
 {
   const char *abi;
 
-  if (TARGET_DISABLE_FPREGS || TARGET_SOFT_FLOAT)
+  if (TARGET_SOFT_FLOAT)
     abi = "soft";
   else
     abi = "hard";
diff --git a/gcc/config/pa/pa.c b/gcc/config/pa/pa.c
index d13021a..21b812e 100644
--- a/gcc/config/pa/pa.c
+++ b/gcc/config/pa/pa.c
@@ -497,7 +497,7 @@ fix_range (const char *const_str)
       break;
 
   if (i > FP_REG_LAST)
-    target_flags |= MASK_DISABLE_FPREGS;
+    target_flags |= MASK_SOFT_FLOAT;
 }
 
 /* Implement the TARGET_OPTION_OVERRIDE hook.  */
@@ -1578,14 +1578,14 @@ hppa_rtx_costs (rtx x, machine_mode mode, int outer_code,
 	}
       else if (mode == DImode)
 	{
-	  if (TARGET_PA_11 && !TARGET_DISABLE_FPREGS && !TARGET_SOFT_FLOAT)
-	    *total = COSTS_N_INSNS (32);
+	  if (TARGET_PA_11 && !TARGET_SOFT_FLOAT && !TARGET_SOFT_MULT)
+	    *total = COSTS_N_INSNS (25);
 	  else
 	    *total = COSTS_N_INSNS (80);
 	}
       else
 	{
-	  if (TARGET_PA_11 && !TARGET_DISABLE_FPREGS && !TARGET_SOFT_FLOAT)
+	  if (TARGET_PA_11 && !TARGET_SOFT_FLOAT && !TARGET_SOFT_MULT)
 	    *total = COSTS_N_INSNS (8);
 	  else
 	    *total = COSTS_N_INSNS (20);
@@ -10627,7 +10627,7 @@ pa_conditional_register_usage (void)
       for (i = 33; i < 56; i += 2)
 	fixed_regs[i] = call_used_regs[i] = 1;
     }
-  if (TARGET_DISABLE_FPREGS || TARGET_SOFT_FLOAT)
+  if (TARGET_SOFT_FLOAT)
     {
       for (i = FP_REG_FIRST; i <= FP_REG_LAST; i++)
 	fixed_regs[i] = call_used_regs[i] = 1;
diff --git a/gcc/config/pa/pa.h b/gcc/config/pa/pa.h
index fbb9604..7a313d6 100644
--- a/gcc/config/pa/pa.h
+++ b/gcc/config/pa/pa.h
@@ -833,7 +833,6 @@ extern int may_call_alloca;
 
 #define INT14_OK_STRICT \
   (TARGET_SOFT_FLOAT                                                   \
-   || TARGET_DISABLE_FPREGS                                            \
    || (TARGET_PA_20 && !TARGET_ELF32))
 
 /* The macros REG_OK_FOR..._P assume that the arg is a REG rtx
diff --git a/gcc/config/pa/pa.md b/gcc/config/pa/pa.md
index c186452..ea6da45 100644
--- a/gcc/config/pa/pa.md
+++ b/gcc/config/pa/pa.md
@@ -5384,7 +5384,7 @@
   "
 {
   operands[4] = gen_rtx_REG (SImode, TARGET_64BIT ? 2 : 31);
-  if (TARGET_PA_11 && !TARGET_DISABLE_FPREGS && !TARGET_SOFT_FLOAT)
+  if (TARGET_PA_11 && !TARGET_SOFT_FLOAT && !TARGET_SOFT_MULT)
     {
       rtx scratch = gen_reg_rtx (DImode);
       operands[1] = force_reg (SImode, operands[1]);
@@ -5402,7 +5402,7 @@
   [(set (match_operand:DI 0 "register_operand" "=f")
 	(mult:DI (zero_extend:DI (match_operand:SI 1 "register_operand" "f"))
 		 (zero_extend:DI (match_operand:SI 2 "register_operand" "f"))))]
-  "TARGET_PA_11 && ! TARGET_DISABLE_FPREGS && ! TARGET_SOFT_FLOAT"
+  "TARGET_PA_11 && ! TARGET_SOFT_FLOAT && ! TARGET_SOFT_MULT"
   "xmpyu %1,%2,%0"
   [(set_attr "type" "fpmuldbl")
    (set_attr "length" "4")])
@@ -5411,7 +5411,7 @@
   [(set (match_operand:DI 0 "register_operand" "=f")
 	(mult:DI (zero_extend:DI (match_operand:SI 1 "register_operand" "f"))
 		 (match_operand:DI 2 "uint32_operand" "f")))]
-  "TARGET_PA_11 && ! TARGET_DISABLE_FPREGS && ! TARGET_SOFT_FLOAT && !TARGET_64BIT"
+  "TARGET_PA_11 && ! TARGET_SOFT_FLOAT && ! TARGET_SOFT_MULT && !TARGET_64BIT"
   "xmpyu %1,%R2,%0"
   [(set_attr "type" "fpmuldbl")
    (set_attr "length" "4")])
@@ -5420,7 +5420,7 @@
   [(set (match_operand:DI 0 "register_operand" "=f")
 	(mult:DI (zero_extend:DI (match_operand:SI 1 "register_operand" "f"))
 		 (match_operand:DI 2 "uint32_operand" "f")))]
-  "TARGET_PA_11 && ! TARGET_DISABLE_FPREGS && ! TARGET_SOFT_FLOAT && TARGET_64BIT"
+  "TARGET_PA_11 && ! TARGET_SOFT_FLOAT && ! TARGET_SOFT_MULT && TARGET_64BIT"
   "xmpyu %1,%2R,%0"
   [(set_attr "type" "fpmuldbl")
    (set_attr "length" "4")])
@@ -5457,8 +5457,8 @@
 		 (match_operand:DI 2 "register_operand" "")))]
   "! optimize_size
    && TARGET_PA_11
-   && ! TARGET_DISABLE_FPREGS
-   && ! TARGET_SOFT_FLOAT"
+   && ! TARGET_SOFT_FLOAT
+   && ! TARGET_SOFT_MULT"
   "
 {
   rtx low_product = gen_reg_rtx (DImode);
@@ -7805,7 +7805,7 @@ add,l %2,%3,%3\;bv,n %%r0(%3)"
       if (GET_CODE (op) == SYMBOL_REF)
 	{
 	  /* Handle special call to buggy powf function.  */
-	  if (TARGET_HPUX && !TARGET_DISABLE_FPREGS && !TARGET_SOFT_FLOAT
+	  if (TARGET_HPUX && !TARGET_SOFT_FLOAT
 	      && !strcmp (targetm.strip_name_encoding (XSTR (op, 0)), "powf"))
 	    call_powf = true;
 
@@ -10260,7 +10260,7 @@ add,l %2,%3,%3\;bv,n %%r0(%3)"
 {
   enum memmodel model;
 
-  if (TARGET_64BIT || TARGET_DISABLE_FPREGS || TARGET_SOFT_FLOAT)
+  if (TARGET_64BIT || TARGET_SOFT_FLOAT)
     FAIL;
 
   model = memmodel_from_int (INTVAL (operands[2]));
@@ -10276,7 +10276,7 @@ add,l %2,%3,%3\;bv,n %%r0(%3)"
   [(set (match_operand:DI 0 "register_operand" "=r")
         (mem:DI (match_operand:SI 1 "register_operand" "r")))
    (clobber (match_scratch:DI 2 "=f"))]
-  "!TARGET_64BIT && !TARGET_DISABLE_FPREGS && !TARGET_SOFT_FLOAT"
+  "!TARGET_64BIT && !TARGET_SOFT_FLOAT"
   "{fldds|fldd} 0(%1),%2\n\t{fstds|fstd} %2,-16(%%sp)\n\t{ldws|ldw} -16(%%sp),%0\n\t{ldws|ldw} -12(%%sp),%R0"
   [(set_attr "type" "move")
    (set_attr "length" "16")])
@@ -10299,7 +10299,7 @@ add,l %2,%3,%3\;bv,n %%r0(%3)"
 	DONE;
     }
 
-  if (TARGET_64BIT || TARGET_DISABLE_FPREGS || TARGET_SOFT_FLOAT)
+  if (TARGET_64BIT || TARGET_SOFT_FLOAT)
     FAIL;
 
   model = memmodel_from_int (INTVAL (operands[2]));
@@ -10317,7 +10317,7 @@ add,l %2,%3,%3\;bv,n %%r0(%3)"
   [(set (mem:DI (match_operand:SI 0 "register_operand" "r,r"))
         (match_operand:DI 1 "reg_or_0_operand" "M,r"))
    (clobber (match_scratch:DI 2 "=X,f"))]
-  "!TARGET_64BIT && !TARGET_DISABLE_FPREGS && !TARGET_SOFT_FLOAT"
+  "!TARGET_64BIT && !TARGET_SOFT_FLOAT"
   "@
    {fstds|fstd} %%fr0,0(%0)
    {stws|stw} %1,-16(%%sp)\n\t{stws|stw} %R1,-12(%%sp)\n\t{fldds|fldd} -16(%%sp),%2\n\t{fstds|fstd} %2,0(%0)"
diff --git a/gcc/config/pa/pa.opt b/gcc/config/pa/pa.opt
index 09660c4..47995f7 100644
--- a/gcc/config/pa/pa.opt
+++ b/gcc/config/pa/pa.opt
@@ -50,8 +50,8 @@ Target Var(TARGET_COHERENT_LDCW) Init(1)
 Use ldcw/ldcd coherent cache-control hint.
 
 mdisable-fpregs
-Target Mask(DISABLE_FPREGS)
-Disable FP regs.
+Target Mask(SOFT_FLOAT)
+Disable FP regs.  Equivalent to -msoft-float.
 
 mdisable-indexing
 Target Mask(DISABLE_INDEXING)
@@ -143,6 +143,10 @@ msoft-float
 Target Mask(SOFT_FLOAT)
 Use software floating point.
 
+msoft-mult
+Target Mask(SOFT_MULT)
+Use software integer multiplication.
+
 msnake
 Target RejectNegative
 Generate PA1.1 code.