Support interrupt handlers with hard-float.

gcc/
	* config/mips/mips.c (mips_compute_frame_info): Allow -mhard-float in
	interrupt attribute.
	(mips_expand_prologue): Disable the floating point unit in an ISR.
	* config/mips/mips.h (SR_COP1): New define.

From-SVN: r225818

gcc/ChangeLog

+2015-07-15  Robert Suchanek  <robert.suchanek@imgtec.com>
+
+	* config/mips/mips.c (mips_compute_frame_info): Allow -mhard-float in
+	interrupt attribute.
+	(mips_expand_prologue): Disable the floating point unit in an ISR.
+	* config/mips/mips.h (SR_COP1): New define.
+
 2015-07-15  Richard Biener  <rguenther@suse.de>
 
 	* genmatch.c (parser::peek, parser::peek_ident): Add argument

gcc/config/mips/mips.c

@@ -10254,8 +10254,6 @@ mips_compute_frame_info (void)
     {
       if (mips_isa_rev < 2)
 	error ("the %<interrupt%> attribute requires a MIPS32r2 processor or greater");
-      else if (TARGET_HARD_FLOAT)
-	error ("the %<interrupt%> attribute requires %<-msoft-float%>");
       else if (TARGET_MIPS16)
 	error ("interrupt handlers cannot be MIPS16 functions");
       else
@@ -11495,6 +11493,14 @@ mips_expand_prologue (void)
 				       GEN_INT (5),
 				       GEN_INT (SR_IE),
 				       gen_rtx_REG (SImode, GP_REG_FIRST)));
+
+	      if (TARGET_HARD_FLOAT)
+		/* Disable COP1 for hard-float.  This will lead to an exception
+		   if floating-point code is executed in an ISR.  */
+		emit_insn (gen_insvsi (gen_rtx_REG (SImode, K1_REG_NUM),
+				       GEN_INT (1),
+				       GEN_INT (SR_COP1),
+				       gen_rtx_REG (SImode, GP_REG_FIRST)));
 	    }
 	  else
 	    {

gcc/config/mips/mips.h

@@ -1807,6 +1807,8 @@ FP_ASM_SPEC "\
 /* Request Interrupt Priority Level is from bit 10 to bit 15 of
    the cause register for the EIC interrupt mode.  */
 #define CAUSE_IPL	10
+/* COP1 Enable is at bit 29 of the status register.  */
+#define SR_COP1         29
 /* Interrupt Priority Level is from bit 10 to bit 15 of the status register.  */
 #define SR_IPL		10
 /* Exception Level is at bit 1 of the status register.  */