[llvm] X86: Add pattern for optimized BLSIC IR form (PR #209814)

[Simon Pilgrim via llvm-commits]

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@@ -909,6 +909,53 @@ define i64 @test_x86_tbm_blsic_u64_sle(i64 %a, i64 %b, i64 %c) nounwind {
   ret i64 %t4
 }
 
+
+define i32 @test_blsic_original(i32 %x) {
+; CHECK-LABEL: test_blsic_original:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    blsicl %edi, %eax
+; CHECK-NEXT:    retq
+  %_2 = xor i32 %x, -1
+  %_0.i = add i32 %x, -1
+  %_0 = or i32 %_0.i, %_2
+  ret i32 %_0
+}
+
+define i32 @test_blsic_optimized(i32 %x) {
+; CHECK-LABEL: test_blsic_optimized:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    blsicl %edi, %eax
+; CHECK-NEXT:    retq
+  %1 = sub i32 0, %x
+  %2 = and i32 %x, %1
+  %3 = xor i32 %2, -1
+  ret i32 %3
+}
+
+define i64 @test_blsic_64_original(i64 %x) {
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RKSimon wrote:

Isn't this the same as the existing test_x86_tbm_blsic_u64 test?

https://github.com/llvm/llvm-project/pull/209814