Extend splitter pattern to reversed condition by swapping then and else rtx. [PR...

Failed to match this instruction:
(set (reg/v:SI 88 [ z ])
    (if_then_else:SI (eq (zero_extract:SI (reg:SI 92)
                (const_int 1 [0x1])
                (zero_extend:SI (subreg:QI (reg:SI 93) 0)))
            (const_int 0 [0]))
        (reg:SI 95)
        (reg:SI 94)))

but it's equal to

(set (reg/v:SI 88 [ z ])
    (if_then_else:SI (ne (zero_extract:SI (reg:SI 92)
                (const_int 1 [0x1])
                (zero_extend:SI (subreg:QI (reg:SI 93) 0)))
            (const_int 0 [0]))
        (reg:SI 94)
        (reg:SI 95)))

which is the exact existing splitter.

The patch will fix below regressions:

On x86-64, r12-7687 caused:

FAIL: gcc.target/i386/bt-5.c scan-assembler-not sar[lq][ \t]
FAIL: gcc.target/i386/bt-5.c scan-assembler-times bt[lq][ \t] 7

gcc/ChangeLog:

	PR target/104982
	* config/i386/i386.md (*jcc_bt<mode>_mask): Extend the
	following splitter to reversed condition.

diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 02f298c..c74edd1 100644 (file)
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -14182,12 +14182,12 @@
 (define_split
   [(set (match_operand:SWI248 0 "register_operand")
        (if_then_else:SWI248
-        (ne
-         (zero_extract:SWI48
-          (match_operand:SWI48 1 "register_operand")
-          (const_int 1)
-          (zero_extend:SI (match_operand:QI 2 "register_operand")))
-         (const_int 0))
+        (match_operator 5 "bt_comparison_operator"
+         [(zero_extract:SWI48
+           (match_operand:SWI48 1 "register_operand")
+           (const_int 1)
+           (zero_extend:SI (match_operand:QI 2 "register_operand")))
+          (const_int 0)])
         (match_operand:SWI248 3 "nonimmediate_operand")
         (match_operand:SWI248 4 "nonimmediate_operand")))]
   "TARGET_USE_BT && TARGET_CMOVE
@@ -14202,6 +14202,8 @@
                             (match_dup 3)
                             (match_dup 4)))]
 {
+  if (GET_CODE (operands[5]) == EQ)
+    std::swap (operands[3], operands[4]);
   operands[2] = lowpart_subreg (SImode, operands[2], QImode);
 })