[RS6000] e500 part of pr71680

The fallback part of HARD_REGNO_CALLER_SAVE_MODE, choose_hard_reg_mode,
returns DFmode for SImode when TARGET_E500_DOUBLE.  This confuses
lra when attempting to save ctr around a call.

	PR target/71680
	* config/rs6000/rs6000.h (HARD_REGNO_CALLER_SAVE_MODE): Return
	SImode for TARGET_E500_DOUBLE when given SImode.

From-SVN: r239317

gcc/ChangeLog

+2016-08-10  Alan Modra  <amodra@gmail.com>
+
+	PR target/71680
+	* config/rs6000/rs6000.h (HARD_REGNO_CALLER_SAVE_MODE): Return
+	SImode for TARGET_E500_DOUBLE when given SImode.
+
 2016-08-09  David Wohlferd  <dw@LimeGreenSocks.com>
 
 	* config/i3836/avx512fintrin.h (_mm512_cvtsepi64_epi32): Remove

gcc/config/rs6000/rs6000.h

@@ -1273,6 +1273,8 @@ enum data_align { align_abi, align_opt, align_both };
    && ((MODE) == VOIDmode || ALTIVEC_OR_VSX_VECTOR_MODE (MODE))		\
    && FP_REGNO_P (REGNO)						\
    ? V2DFmode								\
+   : TARGET_E500_DOUBLE && (MODE) == SImode				\
+   ? SImode								\
    : TARGET_E500_DOUBLE && ((MODE) == VOIDmode || (MODE) == DFmode)	\
    ? DFmode								\
    : !TARGET_E500_DOUBLE && FLOAT128_IBM_P (MODE) && FP_REGNO_P (REGNO)	\