[49/77] Simplify nonzero/num_sign_bits hooks

[Richard Sandiford <richard.sandiford@linaro.org>]

The two implementations of the reg_nonzero_bits and reg_num_sign_bits
hooks ignored the "known_x", "known_mode" and "known_ret" arguments,
so this patch removes them.  It adds a new scalar_int_mode parameter
that specifies the mode of "x".  (This mode might be different from
"mode", which is the mode in which "x" is used.)

2017-07-13  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* rtl.h (rtl_hooks::reg_nonzero_bits): Add a scalar_int_mode
	parameter for the mode of "x".  Remove the "known_x", "known_mode"
	and "known_ret" arguments.  Change the type of the mode argument
	to scalar_int_mode.
	(rtl_hooks:reg_num_sign_bit_copies): Likewise.
	* combine.c (reg_nonzero_bits_for_combine): Update accordingly.
	(reg_num_sign_bit_copies_for_combine): Likewise.
	* rtlanal.c (nonzero_bits1): Likewise.
	(num_sign_bit_copies1): Likewise.
	* rtlhooks-def.h (reg_nonzero_bits_general): Likewise.
	(reg_num_sign_bit_copies_general): Likewise.
	* rtlhooks.c (reg_num_sign_bit_copies_general): Likewise.
	(reg_nonzero_bits_general): Likewise.

Index: gcc/rtl.h
===================================================================
--- gcc/rtl.h	2017-07-13 09:18:32.528352705 +0100
+++ gcc/rtl.h	2017-07-13 09:18:45.761227536 +0100
@@ -3764,10 +3764,10 @@ struct rtl_hooks
 {
   rtx (*gen_lowpart) (machine_mode, rtx);
   rtx (*gen_lowpart_no_emit) (machine_mode, rtx);
-  rtx (*reg_nonzero_bits) (const_rtx, machine_mode, const_rtx, machine_mode,
-			   unsigned HOST_WIDE_INT, unsigned HOST_WIDE_INT *);
-  rtx (*reg_num_sign_bit_copies) (const_rtx, machine_mode, const_rtx, machine_mode,
-				  unsigned int, unsigned int *);
+  rtx (*reg_nonzero_bits) (const_rtx, scalar_int_mode, scalar_int_mode,
+			   unsigned HOST_WIDE_INT *);
+  rtx (*reg_num_sign_bit_copies) (const_rtx, scalar_int_mode, scalar_int_mode,
+				  unsigned int *);
   bool (*reg_truncated_to_mode) (machine_mode, const_rtx);
 
   /* Whenever you add entries here, make sure you adjust rtlhooks-def.h.  */
Index: gcc/combine.c
===================================================================
--- gcc/combine.c	2017-07-13 09:18:44.175354711 +0100
+++ gcc/combine.c	2017-07-13 09:18:45.761227536 +0100
@@ -414,13 +414,12 @@ struct undobuf
 
 static int n_occurrences;
 
-static rtx reg_nonzero_bits_for_combine (const_rtx, machine_mode, const_rtx,
-					 machine_mode,
-					 unsigned HOST_WIDE_INT,
+static rtx reg_nonzero_bits_for_combine (const_rtx, scalar_int_mode,
+					 scalar_int_mode,
 					 unsigned HOST_WIDE_INT *);
-static rtx reg_num_sign_bit_copies_for_combine (const_rtx, machine_mode, const_rtx,
-						machine_mode,
-						unsigned int, unsigned int *);
+static rtx reg_num_sign_bit_copies_for_combine (const_rtx, scalar_int_mode,
+						scalar_int_mode,
+						unsigned int *);
 static void do_SUBST (rtx *, rtx);
 static void do_SUBST_INT (int *, int);
 static void init_reg_last (void);
@@ -10057,17 +10056,15 @@ simplify_and_const_int (rtx x, scalar_in
   return x;
 }
 \f
-/* Given a REG, X, compute which bits in X can be nonzero.
+/* Given a REG X of mode XMODE, compute which bits in X can be nonzero.
    We don't care about bits outside of those defined in MODE.
 
    For most X this is simply GET_MODE_MASK (GET_MODE (MODE)), but if X is
    a shift, AND, or zero_extract, we can do better.  */
 
 static rtx
-reg_nonzero_bits_for_combine (const_rtx x, machine_mode mode,
-			      const_rtx known_x ATTRIBUTE_UNUSED,
-			      machine_mode known_mode ATTRIBUTE_UNUSED,
-			      unsigned HOST_WIDE_INT known_ret ATTRIBUTE_UNUSED,
+reg_nonzero_bits_for_combine (const_rtx x, scalar_int_mode xmode,
+			      scalar_int_mode mode,
 			      unsigned HOST_WIDE_INT *nonzero)
 {
   rtx tem;
@@ -10108,8 +10105,7 @@ reg_nonzero_bits_for_combine (const_rtx
   if (tem)
     {
       if (SHORT_IMMEDIATES_SIGN_EXTEND)
-	tem = sign_extend_short_imm (tem, GET_MODE (x),
-				     GET_MODE_PRECISION (mode));
+	tem = sign_extend_short_imm (tem, xmode, GET_MODE_PRECISION (mode));
 
       return tem;
     }
@@ -10118,9 +10114,9 @@ reg_nonzero_bits_for_combine (const_rtx
     {
       unsigned HOST_WIDE_INT mask = rsp->nonzero_bits;
 
-      if (GET_MODE_PRECISION (GET_MODE (x)) < GET_MODE_PRECISION (mode))
+      if (GET_MODE_PRECISION (xmode) < GET_MODE_PRECISION (mode))
 	/* We don't know anything about the upper bits.  */
-	mask |= GET_MODE_MASK (mode) ^ GET_MODE_MASK (GET_MODE (x));
+	mask |= GET_MODE_MASK (mode) ^ GET_MODE_MASK (xmode);
 
       *nonzero &= mask;
     }
@@ -10128,17 +10124,14 @@ reg_nonzero_bits_for_combine (const_rtx
   return NULL;
 }
 
-/* Return the number of bits at the high-order end of X that are known to
-   be equal to the sign bit.  X will be used in mode MODE; if MODE is
-   VOIDmode, X will be used in its own mode.  The returned value  will always
-   be between 1 and the number of bits in MODE.  */
+/* Given a reg X of mode XMODE, return the number of bits at the high-order
+   end of X that are known to be equal to the sign bit.  X will be used
+   in mode MODE; the returned value will always be between 1 and the
+   number of bits in MODE.  */
 
 static rtx
-reg_num_sign_bit_copies_for_combine (const_rtx x, machine_mode mode,
-				     const_rtx known_x ATTRIBUTE_UNUSED,
-				     machine_mode known_mode
-				     ATTRIBUTE_UNUSED,
-				     unsigned int known_ret ATTRIBUTE_UNUSED,
+reg_num_sign_bit_copies_for_combine (const_rtx x, scalar_int_mode xmode,
+				     scalar_int_mode mode,
 				     unsigned int *result)
 {
   rtx tem;
@@ -10167,7 +10160,7 @@ reg_num_sign_bit_copies_for_combine (con
     return tem;
 
   if (nonzero_sign_valid && rsp->sign_bit_copies != 0
-      && GET_MODE_PRECISION (GET_MODE (x)) == GET_MODE_PRECISION (mode))
+      && GET_MODE_PRECISION (xmode) == GET_MODE_PRECISION (mode))
     *result = rsp->sign_bit_copies;
 
   return NULL;
Index: gcc/rtlanal.c
===================================================================
--- gcc/rtlanal.c	2017-07-13 09:18:45.323262480 +0100
+++ gcc/rtlanal.c	2017-07-13 09:18:45.762227456 +0100
@@ -4449,9 +4449,8 @@ nonzero_bits1 (const_rtx x, scalar_int_m
 
       {
 	unsigned HOST_WIDE_INT nonzero_for_hook = nonzero;
-	rtx new_rtx = rtl_hooks.reg_nonzero_bits (x, mode, known_x,
-					      known_mode, known_ret,
-					      &nonzero_for_hook);
+	rtx new_rtx = rtl_hooks.reg_nonzero_bits (x, xmode, mode,
+						  &nonzero_for_hook);
 
 	if (new_rtx)
 	  nonzero_for_hook &= cached_nonzero_bits (new_rtx, mode, known_x,
@@ -4943,9 +4942,8 @@ num_sign_bit_copies1 (const_rtx x, scala
 
       {
 	unsigned int copies_for_hook = 1, copies = 1;
-	rtx new_rtx = rtl_hooks.reg_num_sign_bit_copies (x, mode, known_x,
-						     known_mode, known_ret,
-						     &copies_for_hook);
+	rtx new_rtx = rtl_hooks.reg_num_sign_bit_copies (x, xmode, mode,
+							 &copies_for_hook);
 
 	if (new_rtx)
 	  copies = cached_num_sign_bit_copies (new_rtx, mode, known_x,
Index: gcc/rtlhooks-def.h
===================================================================
--- gcc/rtlhooks-def.h	2017-02-23 19:54:15.000000000 +0000
+++ gcc/rtlhooks-def.h	2017-07-13 09:18:45.762227456 +0100
@@ -38,13 +38,11 @@ #define RTL_HOOKS_INITIALIZER {			\
 }
 
 extern rtx gen_lowpart_general (machine_mode, rtx);
-extern rtx reg_nonzero_bits_general (const_rtx, machine_mode, const_rtx,
-				     machine_mode,
-				     unsigned HOST_WIDE_INT,
+extern rtx reg_nonzero_bits_general (const_rtx, scalar_int_mode,
+				     scalar_int_mode,
 				     unsigned HOST_WIDE_INT *);
-extern rtx reg_num_sign_bit_copies_general (const_rtx, machine_mode, const_rtx,
-					    machine_mode,
-					    unsigned int, unsigned int *);
+extern rtx reg_num_sign_bit_copies_general (const_rtx, scalar_int_mode,
+					    scalar_int_mode, unsigned int *);
 extern bool reg_truncated_to_mode_general (machine_mode, const_rtx);
 
 #endif /* GCC_RTL_HOOKS_DEF_H */
Index: gcc/rtlhooks.c
===================================================================
--- gcc/rtlhooks.c	2017-07-13 09:18:32.528352705 +0100
+++ gcc/rtlhooks.c	2017-07-13 09:18:45.762227456 +0100
@@ -86,23 +86,15 @@ gen_lowpart_general (machine_mode mode,
 }
 
 rtx
-reg_num_sign_bit_copies_general (const_rtx x ATTRIBUTE_UNUSED,
-				 machine_mode mode ATTRIBUTE_UNUSED,
-                                 const_rtx known_x ATTRIBUTE_UNUSED,
-				 machine_mode known_mode ATTRIBUTE_UNUSED,
-                                 unsigned int known_ret ATTRIBUTE_UNUSED,
-                                 unsigned int *result ATTRIBUTE_UNUSED)
+reg_num_sign_bit_copies_general (const_rtx, scalar_int_mode, scalar_int_mode,
+				 unsigned int *)
 {
   return NULL;
 }
 
 rtx
-reg_nonzero_bits_general (const_rtx x ATTRIBUTE_UNUSED,
-			  machine_mode mode ATTRIBUTE_UNUSED,
-			  const_rtx known_x ATTRIBUTE_UNUSED,
-                          machine_mode known_mode ATTRIBUTE_UNUSED,
-                          unsigned HOST_WIDE_INT known_ret ATTRIBUTE_UNUSED,
-                          unsigned HOST_WIDE_INT *nonzero ATTRIBUTE_UNUSED)
+reg_nonzero_bits_general (const_rtx, scalar_int_mode, scalar_int_mode,
+			  unsigned HOST_WIDE_INT *)
 {
   return NULL;
 }