This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
PATCH: PR target/44844: Wrong _rdrand_uXX intrinsic implementation
- From: "H.J. Lu" <hongjiu dot lu at intel dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Uros Bizjak <ubizjak at gmail dot com>
- Date: Tue, 6 Jul 2010 10:46:02 -0700
- Subject: PATCH: PR target/44844: Wrong _rdrand_uXX intrinsic implementation
- Reply-to: "H.J. Lu" <hjl dot tools at gmail dot com>
Hi,
This patch adds a loop to rdrand<mode> to check if the carry flag is
valid as specified by RDRAND spec. Tested on Linux/x86-64. OK to
install?
Thanks.
H.J.
---
gcc/
2010-07-06 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/
2010-07-06 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.
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 4170711..12e0579 100644
--- a/gcc/config/i386/i386.md
+++ b/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"
diff --git a/gcc/testsuite/gcc.target/i386/rdrand-1.c b/gcc/testsuite/gcc.target/i386/rdrand-1.c
index 9af6bc5..4f6b9e1 100644
--- a/gcc/testsuite/gcc.target/i386/rdrand-1.c
+++ b/gcc/testsuite/gcc.target/i386/rdrand-1.c
@@ -1,6 +1,7 @@
/* { dg-do compile } */
/* { dg-options "-O2 -mrdrnd " } */
/* { dg-final { scan-assembler "rdrand\[ \t]+(%|)ax" } } */
+/* { dg-final { scan-assembler "jnc\[ \t]+" } } */
#include <immintrin.h>
diff --git a/gcc/testsuite/gcc.target/i386/rdrand-2.c b/gcc/testsuite/gcc.target/i386/rdrand-2.c
index f356763..2297383 100644
--- a/gcc/testsuite/gcc.target/i386/rdrand-2.c
+++ b/gcc/testsuite/gcc.target/i386/rdrand-2.c
@@ -1,6 +1,7 @@
/* { dg-do compile } */
/* { dg-options "-O2 -mrdrnd " } */
/* { dg-final { scan-assembler "rdrand\[ \t]+(%|)eax" } } */
+/* { dg-final { scan-assembler "jnc\[ \t]+" } } */
#include <immintrin.h>
diff --git a/gcc/testsuite/gcc.target/i386/rdrand-3.c b/gcc/testsuite/gcc.target/i386/rdrand-3.c
index b18e2e8..17c7c6f 100644
--- a/gcc/testsuite/gcc.target/i386/rdrand-3.c
+++ b/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>