Suppressing MSVC warnings; patch thanks to Peng Cheng!

llvm-svn: 176193

1 files changed, 13 insertions, 3 deletions

diff --git a/llvm/include/llvm/Support/MathExtras.h b/llvm/include/llvm/Support/MathExtras.h
index 214bb6ca26e..d6ae58dc457 100644
--- a/llvm/include/llvm/Support/MathExtras.h
+++ b/llvm/include/llvm/Support/MathExtras.h
@@ -258,7 +258,10 @@ inline unsigned CountTrailingZeros_32(uint32_t Value) {
     4, 7, 17, 0, 25, 22, 31, 15, 29, 10, 12, 6, 0, 21, 14, 9,
     5, 20, 8, 19, 18
   };
-  return Mod37BitPosition[(-Value & Value) % 37];
+  // Replace "-Value" by "1+~Value" in the following commented code to avoid 
+  // MSVC warning C4146
+  //    return Mod37BitPosition[(-Value & Value) % 37];
+  return Mod37BitPosition[((1 + ~Value) & Value) % 37];
 #endif
 }
 
@@ -285,7 +288,10 @@ inline unsigned CountTrailingZeros_64(uint64_t Value) {
     29, 50, 43, 46, 31, 37, 21, 57, 52, 8, 26, 49, 45, 36, 56,
     7, 48, 35, 6, 34, 33, 0
   };
-  return Mod67Position[(-Value & Value) % 67];
+  // Replace "-Value" by "1+~Value" in the following commented code to avoid 
+  // MSVC warning C4146
+  //    return Mod67Position[(-Value & Value) % 67];
+  return Mod67Position[((1 + ~Value) & Value) % 67];
 #endif
 }
 
@@ -420,7 +426,11 @@ int IsInf(double d);
 /// alignment that may be assumed after adding the two together.
 inline uint64_t MinAlign(uint64_t A, uint64_t B) {
   // The largest power of 2 that divides both A and B.
-  return (A | B) & -(A | B);
+  //
+  // Replace "-Value" by "1+~Value" in the following commented code to avoid 
+  // MSVC warning C4146
+  //    return (A | B) & -(A | B);
+  return (A | B) & (1 + ~(A | B));
 }
 
 /// NextPowerOf2 - Returns the next power of two (in 64-bits)