[X86] Add BZHI test case for PR48768

D94856 covered the BMI cases where we had existing tests, this adds a missing BZHI test case

Author: RKSimon

llvm/test/CodeGen/X86/bmi2.ll

@@ -38,6 +38,27 @@ define i32 @bzhi32_load(i32* %x, i32 %y)   {
   ret i32 %tmp
 }
 
+; FIXME: PR48768 - 'bzhi' clears the overflow flag, so we don't need a separate 'test'.
+define i1 @bzhi32_overflow(i32 %x, i32 %y) {
+; X86-LABEL: bzhi32_overflow:
+; X86:       # %bb.0:
+; X86-NEXT:    movl {{[0-9]+}}(%esp), %eax
+; X86-NEXT:    bzhil %eax, {{[0-9]+}}(%esp), %eax
+; X86-NEXT:    testl %eax, %eax
+; X86-NEXT:    setle %al
+; X86-NEXT:    retl
+;
+; X64-LABEL: bzhi32_overflow:
+; X64:       # %bb.0:
+; X64-NEXT:    bzhil %esi, %edi, %eax
+; X64-NEXT:    testl %eax, %eax
+; X64-NEXT:    setle %al
+; X64-NEXT:    retq
+  %tmp = tail call i32 @llvm.x86.bmi.bzhi.32(i32 %x, i32 %y)
+  %cmp = icmp slt i32 %tmp, 1
+  ret i1 %cmp
+}
+
 declare i32 @llvm.x86.bmi.bzhi.32(i32, i32)
 
 define i32 @pdep32(i32 %x, i32 %y)   {