Avoid __popcnt and __popcnt64 intrinsics for MSVC (#2944)

We may need to check the CPU ID or something else before using
those special things on MSVC. To be safe, avoid them for now.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/ir/bits.h b/src/ir/bits.h
index 6b0697280..8b28bb031 100644
--- a/src/ir/bits.h
+++ b/src/ir/bits.h
@@ -43,9 +43,9 @@ struct Bits {
     if (mask == 0) {
       return 0; // trivially not a mask
     }
-    // otherwise, see if adding one turns this into a 1-bit thing, 00011111 + 1
-    // => 00100000
-    if (PopCount(mask + 1) != 1) {
+    // otherwise, see if x & (x + 1) turns this into non-zero value
+    // 00011111 & (00011111 + 1) => 0
+    if (mask & (mask + 1)) {
       return 0;
     }
     // this is indeed a mask