Add clobber_reg

2014-04-25  Tom de Vries  <tom@codesourcery.com>

	* expr.c (clobber_reg_mode): New function.
	* expr.h (clobber_reg): New function.

From-SVN: r209800

gcc/ChangeLog

 2014-04-25  Tom de Vries  <tom@codesourcery.com>
 
+	* expr.c (clobber_reg_mode): New function.
+	* expr.h (clobber_reg): New function.
+
+2014-04-25  Tom de Vries  <tom@codesourcery.com>
+
 	* rtlanal.c (find_all_hard_reg_sets): Note INSN_CALL_FUNCTION_USAGE
 	clobbers.
 

gcc/expr.c

@@ -2396,6 +2396,18 @@ use_reg_mode (rtx *call_fusage, rtx reg, enum machine_mode mode)
     = gen_rtx_EXPR_LIST (mode, gen_rtx_USE (VOIDmode, reg), *call_fusage);
 }
 
+/* Add a CLOBBER expression for REG to the (possibly empty) list pointed
+   to by CALL_FUSAGE.  REG must denote a hard register.  */
+
+void
+clobber_reg_mode (rtx *call_fusage, rtx reg, enum machine_mode mode)
+{
+  gcc_assert (REG_P (reg) && REGNO (reg) < FIRST_PSEUDO_REGISTER);
+
+  *call_fusage
+    = gen_rtx_EXPR_LIST (mode, gen_rtx_CLOBBER (VOIDmode, reg), *call_fusage);
+}
+
 /* Add USE expressions to *CALL_FUSAGE for each of NREGS consecutive regs,
    starting at REGNO.  All of these registers must be hard registers.  */
 

gcc/expr.h

@@ -346,6 +346,7 @@ extern void copy_blkmode_from_reg (rtx, rtx, tree);
 /* Mark REG as holding a parameter for the next CALL_INSN.
    Mode is TYPE_MODE of the non-promoted parameter, or VOIDmode.  */
 extern void use_reg_mode (rtx *, rtx, enum machine_mode);
+extern void clobber_reg_mode (rtx *, rtx, enum machine_mode);
 
 extern rtx copy_blkmode_to_reg (enum machine_mode, tree);
 
@@ -356,6 +357,13 @@ use_reg (rtx *fusage, rtx reg)
   use_reg_mode (fusage, reg, VOIDmode);
 }
 
+/* Mark REG as clobbered by the call with FUSAGE as CALL_INSN_FUNCTION_USAGE.  */
+static inline void
+clobber_reg (rtx *fusage, rtx reg)
+{
+  clobber_reg_mode (fusage, reg, VOIDmode);
+}
+
 /* Mark NREGS consecutive regs, starting at REGNO, as holding parameters
    for the next CALL_INSN.  */
 extern void use_regs (rtx *, int, int);