[gcc r14-6815] LoongArch: Add sign_extend pattern for 32-bit rotate shift

[Xi Ruoyao]

https://gcc.gnu.org/g:310dc75e7004d8b8e39c6f258b28b2165ad4193c

commit r14-6815-g310dc75e7004d8b8e39c6f258b28b2165ad4193c
Author: Xi Ruoyao <xry111@xry111.site>
Date:   Sun Dec 17 04:26:23 2023 +0800

    LoongArch: Add sign_extend pattern for 32-bit rotate shift
    
    Remove a redundant sign extension.
    
    gcc/ChangeLog:
    
            * config/loongarch/loongarch.md (rotrsi3_extend): New
            define_insn.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/loongarch/rotrw.c: New test.

Diff:
---
 gcc/config/loongarch/loongarch.md          | 10 ++++++++++
 gcc/testsuite/gcc.target/loongarch/rotrw.c | 17 +++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/gcc/config/loongarch/loongarch.md b/gcc/config/loongarch/loongarch.md
index b48e8b53524..7021105b241 100644
--- a/gcc/config/loongarch/loongarch.md
+++ b/gcc/config/loongarch/loongarch.md
@@ -2893,6 +2893,16 @@
   [(set_attr "type" "shift,shift")
    (set_attr "mode" "<MODE>")])
 
+(define_insn "rotrsi3_extend"
+  [(set (match_operand:DI 0 "register_operand" "=r,r")
+	(sign_extend:DI
+	  (rotatert:SI (match_operand:SI 1 "register_operand" "r,r")
+		       (match_operand:SI 2 "arith_operand" "r,I"))))]
+  "TARGET_64BIT"
+  "rotr%i2.w\t%0,%1,%2"
+  [(set_attr "type" "shift,shift")
+   (set_attr "mode" "SI")])
+
 ;; The following templates were added to generate "bstrpick.d + alsl.d"
 ;; instruction pairs.
 ;; It is required that the values of const_immalsl_operand and
diff --git a/gcc/testsuite/gcc.target/loongarch/rotrw.c b/gcc/testsuite/gcc.target/loongarch/rotrw.c
new file mode 100644
index 00000000000..6ed45e8b86c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/rotrw.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler "rotr\\.w\t\\\$r4,\\\$r4,\\\$r5" } } */
+/* { dg-final { scan-assembler "rotri\\.w\t\\\$r4,\\\$r4,5" } } */
+/* { dg-final { scan-assembler-not "slli\\.w" } } */
+
+unsigned
+rotr (unsigned a, unsigned b)
+{
+  return a >> b | a << 32 - b;
+}
+
+unsigned
+rotri (unsigned a)
+{
+  return a >> 5 | a << 27;
+}