The attached patch contains __builtin_arm_rbit which generates RBIT
instruction for ARM targets.
Please let me know if you any questions or comments, or commit this
patch for me as I do not have write access to SVN.
Thanks
Ayan
commit a692b5b4965840babbdaf5e2b9b1feb1995d351d
Author: Ayan Shafqat <ayan.x.shaf...@gmail.com>
Date: Mon Jun 17 21:46:54 2019 -0400
Implementing RBIT builtin as described in ACLE doc
ARM's RBIT instruction is used to reverse the bit order
of a word. This is present in ARMv6 and above in both
ARM and Thumb modes. This is also specified as an intrinsic
function in ACLE documentation.
This commit implements the GCC builtin for ARM target for
RBIT instruction, __builtin_arm_rbit. Also, this implements
the intrinsic functions as stated in ARM ACLE documentation,
which are listed below:
uint32_t __rbit(uint32_t x);
unsigned long __rbitl(unsigned long x);
uint64_t __rbitll(uint64_t x);
Note: __rbitll is implemented as two calls to __rbit. I know
this is not how it's done in AArch64, but this is what I can
do for now.
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index ae582172ab9..83dcb7b411c 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -11568,6 +11568,13 @@
[(set_attr "predicable" "yes")
(set_attr "type" "clz")])
+(define_insn "rbit"
+ [(set (match_operand:SI 0 "s_register_operand" "=r")
+ (unspec:SI [(match_operand:SI 1 "s_register_operand" "r")]
UNSPEC_RBIT))]
+ "TARGET_32BIT && arm_arch_thumb2"
+ "rbit%?\\t%0, %1"
+ [(set_attr "predicable" "yes")])
+
(define_insn "rbitsi2"
[(set (match_operand:SI 0 "s_register_operand" "=r")
(unspec:SI [(match_operand:SI 1 "s_register_operand" "r")]
UNSPEC_RBIT))]
diff --git a/gcc/config/arm/arm_acle.h b/gcc/config/arm/arm_acle.h
index 2c7acc698ea..ce1b102444b 100644
--- a/gcc/config/arm/arm_acle.h
+++ b/gcc/config/arm/arm_acle.h
@@ -168,6 +168,29 @@ __arm_mrrc2 (const unsigned int __coproc, const
unsigned int __opc1,
{
return __builtin_arm_mrrc2 (__coproc, __opc1, __CRm);
}
+
+__extension__ static __inline uint32_t __attribute__ ((__always_inline__))
+__rbit(uint32_t __op1)
+{
+ return __builtin_arm_rbit(__op1);
+}
+
+__extension__ static __inline uint64_t __attribute__ ((__always_inline__))
+__rbitll(uint64_t __op1)
+{
+ return (((uint64_t)__rbit(__op1)) << 32U) | __rbit(__op1 >> 32U);
+}
+
+__extension__ static __inline unsigned long __attribute__
((__always_inline__))
+__rbitl(unsigned long __op1)
+{
+#if __SIZEOF_LONG__ == 4
+ return __rbit(__op1);
+#else
+ return __rbitll(__op1);
+#endif
+}
+
#endif /* __ARM_ARCH >= 6. */
#endif /* __ARM_ARCH >= 6 || defined (__ARM_ARCH_5TE__). */
#endif /* __ARM_ARCH >= 5. */
diff --git a/gcc/config/arm/arm_acle_builtins.def
b/gcc/config/arm/arm_acle_builtins.def
index b2438d66da2..ecb3be491fc 100644
--- a/gcc/config/arm/arm_acle_builtins.def
+++ b/gcc/config/arm/arm_acle_builtins.def
@@ -24,6 +24,7 @@ VAR1 (UBINOP, crc32w, si)
VAR1 (UBINOP, crc32cb, si)
VAR1 (UBINOP, crc32ch, si)
VAR1 (UBINOP, crc32cw, si)
+VAR1 (UBINOP, rbit, si)
VAR1 (CDP, cdp, void)
VAR1 (CDP, cdp2, void)
VAR1 (LDC, ldc, void)
diff --git a/gcc/testsuite/gcc.target/arm/acle/rbit.c
b/gcc/testsuite/gcc.target/arm/acle/rbit.c
new file mode 100644
index 00000000000..7803dd33615
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/acle/rbit.c
@@ -0,0 +1,18 @@
+/* Test the crc32d ACLE intrinsic. */
+
+/* { dg-do assemble } */
+/* { dg-require-effective-target arm_crc_ok } */
+/* { dg-options "-save-temps -O0" } */
+/* { dg-add-options arm_crc } */
+
+#include "arm_acle.h"
+
+void test_rbit (void)
+{
+ uint32_t out_uint32_t;
+ uint32_t arg0_uint32_t;
+
+ out_uint32_t = __rbit (arg0_uint32_t);
+}
+
+/* { dg-final { scan-assembler-times "rbit\t...?, ...?\n" 2 } } */
