Retry rdrand if the carry flag isn't valid.

gcc/

2010-07-07  H.J. Lu  <hongjiu.lu@intel.com>

	PR target/44844
	* config/i386/i386.md (rdrand<mode>): Changed to expand to
	retry if the carry flag isn't valid.
	(rdrand<mode>_1): New.

gcc/testsuite/

2010-07-07  H.J. Lu  <hongjiu.lu@intel.com>

	PR target/44844
	* gcc.target/i386/rdrand-1.c: Scan "jnc".
	* gcc.target/i386/rdrand-2.c: Likewise.
	* gcc.target/i386/rdrand-3.c: Likewise.

From-SVN: r161910

gcc/ChangeLog

+2010-07-07  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR target/44844
+	* config/i386/i386.md (rdrand<mode>): Changed to expand to
+	retry if the carry flag isn't valid.
+	(rdrand<mode>_1): New.
+
 2010-07-07  Richard Guenther  <rguenther@suse.de>
 
 	PR middle-end/44790

gcc/config/i386/i386.md

@@ -18494,7 +18494,32 @@
   [(set_attr "type" "other")
    (set_attr "prefix_extra" "2")])
 
-(define_insn "rdrand<mode>"
+(define_expand "rdrand<mode>"
+  [(set (match_operand:SWI248 0 "register_operand" "=r")
+	(unspec_volatile:SWI248 [(const_int 0)] UNSPECV_RDRAND))]
+  "TARGET_RDRND"
+{
+  rtx retry_label, insn, ccc;
+
+  retry_label = gen_label_rtx ();
+
+  emit_label (retry_label);
+
+  /* Generate rdrand.  */
+  emit_insn (gen_rdrand<mode>_1 (operands[0]));
+
+  /* Retry if the carry flag isn't valid.  */
+  ccc = gen_rtx_REG (CCCmode, FLAGS_REG);
+  ccc = gen_rtx_EQ (VOIDmode, ccc, const0_rtx);
+  ccc = gen_rtx_IF_THEN_ELSE (VOIDmode, ccc, pc_rtx,
+			      gen_rtx_LABEL_REF (VOIDmode, retry_label));
+  insn = emit_jump_insn (gen_rtx_SET (VOIDmode, pc_rtx, ccc));
+  JUMP_LABEL (insn) = retry_label;
+
+  DONE;
+})
+
+(define_insn "rdrand<mode>_1"
   [(set (match_operand:SWI248 0 "register_operand" "=r")
 	(unspec_volatile:SWI248 [(const_int 0)] UNSPECV_RDRAND))]
   "TARGET_RDRND"

gcc/testsuite/ChangeLog

+2010-07-07  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR target/44844
+	* gcc.target/i386/rdrand-1.c: Scan "jnc".
+	* gcc.target/i386/rdrand-2.c: Likewise.
+	* gcc.target/i386/rdrand-3.c: Likewise.
+
 2010-07-07  Jan Hubicka  <jh@suse.cz>
 
 	PR middle-end/44813

gcc/testsuite/gcc.target/i386/rdrand-1.c

 /* { dg-do compile } */
 /* { dg-options "-O2 -mrdrnd " } */
 /* { dg-final { scan-assembler "rdrand\[ \t]+(%|)ax" } } */
+/* { dg-final { scan-assembler "jnc\[ \t]+" } } */
 
 #include <immintrin.h>
 

gcc/testsuite/gcc.target/i386/rdrand-2.c

 /* { dg-do compile } */
 /* { dg-options "-O2 -mrdrnd " } */
 /* { dg-final { scan-assembler "rdrand\[ \t]+(%|)eax" } } */
+/* { dg-final { scan-assembler "jnc\[ \t]+" } } */
 
 #include <immintrin.h>
 

gcc/testsuite/gcc.target/i386/rdrand-3.c

@@ -2,6 +2,7 @@
 /* { dg-require-effective-target lp64 } */
 /* { dg-options "-O2 -mrdrnd " } */
 /* { dg-final { scan-assembler "rdrand\[ \t]+(%|)rax" } } */
+/* { dg-final { scan-assembler "jnc\[ \t]+" } } */
 
 #include <immintrin.h>