[gcc(refs/vendors/riscv/heads/gcc-15-with-riscv-opts)] [RISC-V][PR target/122106] Add missing predicate on crc expanders

[Jeff Law]

https://gcc.gnu.org/g:4c51850249d3137ef1d08f30031ebcae5ac08fa7

commit 4c51850249d3137ef1d08f30031ebcae5ac08fa7
Author: Jeff Law <jlaw@ventanamicro.com>
Date:   Wed Oct 1 15:12:49 2025 -0600

    [RISC-V][PR target/122106] Add missing predicate on crc expanders
    
    This is a minor bug in the CRC code for RISC-V.
    
    Essentially in the expander we have an operand without a predicate.  So it
    matches anything.  But that operand really has to be a CONST_INT.  So this
    patch adds the missing predicate.  I noticed we had constraints on our
    define_expand.  It doesn't hurt anything, but they're never used and can easily
    get out of date, so this removes the unnecessary constraints.
    
    Tested on riscv32-elf and riscv64-elf.  Bootstrap & regression test on the
    Pioneer is in flight and should finish in the next few hours.
    
    Pushing to the trunk once CI confirms it's OK.
    
            PR target/122106
    gcc/
            * config/riscv/bitmanip.md (crc expanders): Add predicate for
            polynomial argument.  Drop unnecessary constraints.
    
    gcc/testsuite/
    
            * gcc.target/riscv/pr122106.c: New test.
    
    (cherry picked from commit c866a8a88242833f64fe25e04e4ad4c097daec34)

Diff:
---
 gcc/config/riscv/bitmanip.md              | 16 ++++++++--------
 gcc/testsuite/gcc.target/riscv/pr122106.c |  3 +++
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/gcc/config/riscv/bitmanip.md b/gcc/config/riscv/bitmanip.md
index 5fd139ac9c14..59b71ed263b0 100644
--- a/gcc/config/riscv/bitmanip.md
+++ b/gcc/config/riscv/bitmanip.md
@@ -1218,13 +1218,13 @@
 ;; Reversed CRC 8, 16, 32 for TARGET_64
 (define_expand "crc_rev<ANYI1:mode><ANYI:mode>4"
 	;; return value (calculated CRC)
-  [(set (match_operand:ANYI 0 "register_operand" "=r")
+  [(set (match_operand:ANYI 0 "register_operand")
 		      ;; initial CRC
-	(unspec:ANYI [(match_operand:ANYI 1 "register_operand" "r")
+	(unspec:ANYI [(match_operand:ANYI 1 "register_operand")
 		      ;; data
-		      (match_operand:ANYI1 2 "register_operand" "r")
+		      (match_operand:ANYI1 2 "register_operand")
 		      ;; polynomial without leading 1
-		      (match_operand:ANYI 3)]
+		      (match_operand:ANYI 3 "const_int_operand")]
 		      UNSPEC_CRC_REV))]
   /* We don't support the case when data's size is bigger than CRC's size.  */
   "<ANYI:MODE>mode >= <ANYI1:MODE>mode"
@@ -1258,13 +1258,13 @@
 ;; CRC 8, 16, (32 for TARGET_64)
 (define_expand "crc<SUBX1:mode><SUBX:mode>4"
 	;; return value (calculated CRC)
-  [(set (match_operand:SUBX 0 "register_operand" "=r")
+  [(set (match_operand:SUBX 0 "register_operand")
 		      ;; initial CRC
-	(unspec:SUBX [(match_operand:SUBX 1 "register_operand" "r")
+	(unspec:SUBX [(match_operand:SUBX 1 "register_operand")
 		      ;; data
-		      (match_operand:SUBX1 2 "register_operand" "r")
+		      (match_operand:SUBX1 2 "register_operand")
 		      ;; polynomial without leading 1
-		      (match_operand:SUBX 3)]
+		      (match_operand:SUBX 3 "const_int_operand")]
 		      UNSPEC_CRC))]
   /* We don't support the case when data's size is bigger than CRC's size.  */
   "(TARGET_ZBKC || TARGET_ZBC || TARGET_ZVBC)
diff --git a/gcc/testsuite/gcc.target/riscv/pr122106.c b/gcc/testsuite/gcc.target/riscv/pr122106.c
new file mode 100644
index 000000000000..b0345b029701
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/pr122106.c
@@ -0,0 +1,3 @@
+/* { dg-do compile } */
+
+short foo() { return __builtin_rev_crc16_data16(0, 0, 0); }