This patch adds support for a possible new variant of the vector rotate left
instruction that might be added to a future PowerPC. This variant (xvrlw) can
use any VSX register instead of requiring only Altivec registers.
I have committed all of the patches in my backlog (dense math registers, other
-mcpu=future instructions, random bug fixes, support for _Float16 and
__bfloat16, and optimizations for vector logical operations on power10/power11)
into the IBM vendor branch:
vendors/ibm/gcc-17-future
2026-07-01 Michael Meissner <[email protected]>
gcc/
* config/rs6000/altivec.md (xvrlw): New insn.
* config/rs6000/rs6000.h (TARGET_XVRLW): New macro.
gcc/testsuite/
* gcc.target/powerpc/vector-rotate-left.c: New test.
---
gcc/config/rs6000/altivec.md | 14 ++++++++
gcc/config/rs6000/rs6000.h | 3 ++
.../gcc.target/powerpc/vector-rotate-left.c | 34 +++++++++++++++++++
3 files changed, 51 insertions(+)
create mode 100644 gcc/testsuite/gcc.target/powerpc/vector-rotate-left.c
diff --git a/gcc/config/rs6000/altivec.md b/gcc/config/rs6000/altivec.md
index dbe24c450e1..95433ce500a 100644
--- a/gcc/config/rs6000/altivec.md
+++ b/gcc/config/rs6000/altivec.md
@@ -2006,6 +2006,20 @@ (define_insn "altivec_vpku<VI_char>um_direct"
}
[(set_attr "type" "vecperm")])
+;; -mcpu=future adds a vector rotate left word variant. There is no vector
+;; byte/half-word/double-word/quad-word rotate left. This insn occurs before
+;; altivec_vrl<VI_char> and will match for -mcpu=future, while other cpus will
+;; match the generic insn.
+(define_insn "*xvrlw"
+ [(set (match_operand:V4SI 0 "register_operand" "=v,wa")
+ (rotate:V4SI (match_operand:V4SI 1 "register_operand" "v,wa")
+ (match_operand:V4SI 2 "register_operand" "v,wa")))]
+ "TARGET_XVRLW"
+ "@
+ vrlw %0,%1,%2
+ xvrlw %x0,%x1,%x2"
+ [(set_attr "type" "vecsimple")])
+
(define_insn "altivec_vrl<VI_char>"
[(set (match_operand:VI2 0 "register_operand" "=v")
(rotate:VI2 (match_operand:VI2 1 "register_operand" "v")
diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
index eef25768b5a..3064db2a7e4 100644
--- a/gcc/config/rs6000/rs6000.h
+++ b/gcc/config/rs6000/rs6000.h
@@ -571,6 +571,9 @@ extern int rs6000_vector_align[];
below. */
#define RS6000_FN_TARGET_INFO_HTM 1
+/* Whether we have XVRLW support. */
+#define TARGET_XVRLW TARGET_FUTURE
+
/* Whether the various reciprocal divide/square root estimate instructions
exist, and whether we should automatically generate code for the instruction
by default. */
diff --git a/gcc/testsuite/gcc.target/powerpc/vector-rotate-left.c
b/gcc/testsuite/gcc.target/powerpc/vector-rotate-left.c
new file mode 100644
index 00000000000..f9e87ad4bfc
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/vector-rotate-left.c
@@ -0,0 +1,34 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target powerpc_future_ok } */
+/* { dg-options "-mdejagnu-cpu=future -O2" } */
+
+/* Test whether the xvrl (vector word rotate left using VSX registers insead of
+ Altivec registers is generated. */
+
+#include <altivec.h>
+
+typedef vector unsigned int v4si_t;
+
+v4si_t
+rotl_v4si_scalar (v4si_t x, unsigned long n)
+{
+ __asm__ (" # %x0" : "+f" (x));
+ return (x << n) | (x >> (32 - n)); /* xvrlw. */
+}
+
+v4si_t
+rotr_v4si_scalar (v4si_t x, unsigned long n)
+{
+ __asm__ (" # %x0" : "+f" (x));
+ return (x >> n) | (x << (32 - n)); /* xvrlw. */
+}
+
+v4si_t
+rotl_v4si_vector (v4si_t x, v4si_t y)
+{
+ __asm__ (" # %x0" : "+f" (x)); /* xvrlw. */
+ return vec_rl (x, y);
+}
+
+/* { dg-final { scan-assembler-times {\mxvrlw\M} 3 } } */
+/* { dg-final { scan-assembler-not {\mvrlw\M} } } */
--
2.54.0
--
Michael Meissner, IBM
PO Box 98, Ayer, Massachusetts, USA, 01432
email: [email protected]
