[RISC-V][PR target/120223] Don't use bset/binv for XTHEADBS

Thead has the XTHEADBB extension which has a lot of overlap with Zbb.  I made
the incorrect assumption that XTHEADBS would largely be like Zbs when
generalizing Shreya's work.

As a result we can't use the operation synthesis code for IOR/XOR because we
don't have binv/bset like capabilities.  I should have double checked on
XTHEADBS, my bad.

Anyway, the fix is trivial.  Don't allow bset/binv based on XTHEADBS.

Already spun in my tester.  Spinning in the pre-commit CI system now.

	PR target/120223
gcc/
	* config/riscv/riscv.cc (synthesize_ior_xor): XTHEADBS does not have
	single bit manipulations.

gcc/testsuite/

	* gcc.target/riscv/pr120223.c: New test.

diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index d28aee4b4398c889f88da0f78bef8a4d4f476102..d996965d095340d2aca5277c8bafee26040338e2 100644 (file)
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -14227,7 +14227,7 @@ synthesize_ior_xor (rtx_code code, rtx operands[3])
 {
   /* Trivial cases that don't need synthesis.  */
   if (SMALL_OPERAND (INTVAL (operands[2]))
-     || ((TARGET_ZBS || TARGET_XTHEADBS || TARGET_ZBKB)
+     || ((TARGET_ZBS || TARGET_ZBKB)
         && single_bit_mask_operand (operands[2], word_mode)))
     return false;
 
@@ -14264,7 +14264,7 @@ synthesize_ior_xor (rtx_code code, rtx operands[3])
   /* If we're flipping all but a small number of bits we can pre-flip
      the outliers, then flip all the bits, which would restore those
      bits that were pre-flipped. */
-  if ((TARGET_ZBS || TARGET_XTHEADBS || TARGET_ZBKB)
+  if ((TARGET_ZBS || TARGET_ZBKB)
       && budget < 0
       && code == XOR
       && popcount_hwi (~INTVAL (operands[2])) < original_budget)

diff --git a/gcc/testsuite/gcc.target/riscv/pr120223.c b/gcc/testsuite/gcc.target/riscv/pr120223.c
new file mode 100644 (file)
index 0000000..fae21b6
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/pr120223.c
@@ -0,0 +1,4 @@
+/* { dg-do compile } */
+/* { dg-options "-mcpu=thead-c906" }  */
+long foo(long x) { return x ^ 0x80000000; }
+