Generate 128-bit divide/modulus

[Michael Meissner]

Generate 128-bit divide/modulus.

This patch adds support for the VDIVSQ, VDIVUQ, VMODSQ, and VMODUQ
instructions to do 128-bit arithmetic.

I have tested this on 3 compilers:
    * Power9 little endian, --with-cpu=power9
    * Power8 big endian, --with-cpu=power8, both 32/64-bit tested
    * Power10 little endian, --with-cpu=power10

There were no issues found in the runs.  Can I check this into the master
branch and later into the GCC 11 branch after a soak-in period?

gcc/
2021-06-03  Michael Meissner  <meissner@linux.ibm.com>

	PR target/100809
	* config/rs6000/rs6000.md (udivti3): New insn.
	(divti3): New insn.
	(umodti3): New insn.
	(modti3): New insn.

gcc/testsuite/
2021-06-03  Michael Meissner  <meissner@linux.ibm.com>

	PR target/100809
	* gcc.target/powerpc/p10-vdiv-vmod.c: New test.
---
 gcc/config/rs6000/rs6000.md                   | 34 +++++++++++++++++++
 .../gcc.target/powerpc/p10-vdivq-vmodq.c      | 27 +++++++++++++++
 2 files changed, 61 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/powerpc/p10-vdivq-vmodq.c

diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index 2517901f239..e70dbe409df 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -3234,6 +3234,14 @@ (define_insn "udiv<mode>3"
   [(set_attr "type" "div")
    (set_attr "size" "<bits>")])
 
+(define_insn "udivti3"
+  [(set (match_operand:TI 0 "altivec_register_operand" "=v")
+        (udiv:TI (match_operand:TI 1 "altivec_register_operand" "v")
+		 (match_operand:TI 2 "altivec_register_operand" "v")))]
+  "TARGET_POWER10 && TARGET_POWERPC64"
+  "vdivuq %0,%1,%2"
+  [(set_attr "type" "vecdiv")
+   (set_attr "size" "128")])
 
 ;; For powers of two we can do sra[wd]i/addze for divide and then adjust for
 ;; modulus.  If it isn't a power of two, force operands into register and do
@@ -3324,6 +3332,15 @@ (define_insn_and_split "*div<mode>3_sra_dot2"
    (set_attr "length" "8,12")
    (set_attr "cell_micro" "not")])
 
+(define_insn "divti3"
+  [(set (match_operand:TI 0 "altivec_register_operand" "=v")
+        (div:TI (match_operand:TI 1 "altivec_register_operand" "v")
+		(match_operand:TI 2 "altivec_register_operand" "v")))]
+  "TARGET_POWER10 && TARGET_POWERPC64"
+  "vdivsq %0,%1,%2"
+  [(set_attr "type" "vecdiv")
+   (set_attr "size" "128")])
+
 (define_expand "mod<mode>3"
   [(set (match_operand:GPR 0 "gpc_reg_operand")
 	(mod:GPR (match_operand:GPR 1 "gpc_reg_operand")
@@ -3424,6 +3441,23 @@ (define_peephole2
 	(minus:GPR (match_dup 1)
 		   (match_dup 3)))])
 
+(define_insn "umodti3"
+  [(set (match_operand:TI 0 "altivec_register_operand" "=v")
+        (umod:TI (match_operand:TI 1 "altivec_register_operand" "v")
+		 (match_operand:TI 2 "altivec_register_operand" "v")))]
+  "TARGET_POWER10 && TARGET_POWERPC64"
+  "vmoduq %0,%1,%2"
+  [(set_attr "type" "vecdiv")
+   (set_attr "size" "128")])
+
+(define_insn "modti3"
+  [(set (match_operand:TI 0 "altivec_register_operand" "=v")
+        (mod:TI (match_operand:TI 1 "altivec_register_operand" "v")
+		(match_operand:TI 2 "altivec_register_operand" "v")))]
+  "TARGET_POWER10 && TARGET_POWERPC64"
+  "vmodsq %0,%1,%2"
+  [(set_attr "type" "vecdiv")
+   (set_attr "size" "128")])
 
 ;; Logical instructions
 ;; The logical instructions are mostly combined by using match_operator,
diff --git a/gcc/testsuite/gcc.target/powerpc/p10-vdivq-vmodq.c b/gcc/testsuite/gcc.target/powerpc/p10-vdivq-vmodq.c
new file mode 100644
index 00000000000..cd29b0a4b6b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/p10-vdivq-vmodq.c
@@ -0,0 +1,27 @@
+/* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target power10_ok } */
+/* { dg-options "-mdejagnu-cpu=power10 -O2" } */
+
+unsigned __int128 u_div(unsigned __int128 a, unsigned __int128 b)
+{
+   return a/b;
+}
+
+unsigned __int128 u_mod(unsigned __int128 a, unsigned __int128 b)
+{
+   return a%b;
+}
+__int128 s_div(__int128 a, __int128 b)
+{
+   return a/b;
+}
+
+__int128 s_mod(__int128 a, __int128 b)
+{
+   return a%b;
+}
+
+/* { dg-final { scan-assembler {\mvdivsq\M} } } */
+/* { dg-final { scan-assembler {\mvdivuq\M} } } */
+/* { dg-final { scan-assembler {\mvmodsq\M} } } */
+/* { dg-final { scan-assembler {\mvmoduq\M} } } */
-- 
2.31.1


-- 
Michael Meissner, IBM
IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA
email: meissner@linux.ibm.com, phone: +1 (978) 899-4797