Index: lib/Transforms/InstCombine/InstCombineSelect.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -1480,6 +1480,38 @@
     }
   }
 
+  /*
+    Try to fold a select of bittest. There are two patterns:
+      %2 = and i32 %X, %Y     # Mask A
+      %3 = icmp eq i32 %2, 0
+      %4 = and i32 %X, 1      # Mask B
+      %5 = select i1 %3, i32 %4, i32 1
+    or
+      %2 = and i32 %X, %Y     # Mask A
+      %3 = icmp eq i32 %2, 0
+      %S = lshr i32 %X, C     # C u< 32
+      %5 = and i32 %S, 1      # Mask B
+      %6 = select i1 %3, i32 %5, i32 1
+  */
+  Value *X, *Y;
+  uint64_t C = 0;
+  ICmpInst::Predicate EqPred;
+  if (match(CondVal, m_ICmp(EqPred, m_And(m_Value(X), m_Value(Y)), m_Zero())) &&
+      ICmpInst::Predicate::ICMP_EQ == EqPred && match(FalseVal, m_One())) {
+    // The TrueVal can be one of:
+    //   and (lshr %X, C), 1
+    //   and       %X,     1      (in which case C is 0)
+    if (match(TrueVal, m_And(m_Value(X), m_One())) ||
+        match(TrueVal, m_And(m_LShr(m_Value(X), m_ConstantInt(C)), m_One()))) {
+      // These will be folded by this very pass right away.
+      Value *MaskB = Builder.CreateShl(ConstantInt::get(SelType, 1), C);
+      Value *NewMask = Builder.CreateOr(Y, MaskB);
+      Value *MaskedX = Builder.CreateAnd(X, NewMask);
+      Value *ICmpNeZero = Builder.CreateIsNotNull(MaskedX);
+      return new ZExtInst(ICmpNeZero, SelType);
+    }
+  }
+
   // See if we are selecting two values based on a comparison of the two values.
   if (FCmpInst *FCI = dyn_cast<FCmpInst>(CondVal)) {
     if (FCI->getOperand(0) == TrueVal && FCI->getOperand(1) == FalseVal) {
Index: test/Transforms/InstCombine/select-of-bittest.ll
===================================================================
--- test/Transforms/InstCombine/select-of-bittest.ll
+++ test/Transforms/InstCombine/select-of-bittest.ll
@@ -8,12 +8,9 @@
 
 define i32 @f_m2(i32) {
 ; CHECK-LABEL: @f_m2(
-; CHECK-NEXT:    [[TMP2:%.*]] = and i32 [[TMP0:%.*]], 1
-; CHECK-NEXT:    [[TMP3:%.*]] = icmp eq i32 [[TMP2]], 0
-; CHECK-NEXT:    [[TMP4:%.*]] = lshr i32 [[TMP0]], 1
-; CHECK-NEXT:    [[TMP5:%.*]] = and i32 [[TMP4]], 1
-; CHECK-NEXT:    [[TMP6:%.*]] = select i1 [[TMP3]], i32 [[TMP5]], i32 1
-; CHECK-NEXT:    ret i32 [[TMP6]]
+; CHECK-NEXT:    [[TMP2:%.*]] = lshr i32 [[TMP0:%.*]], 1
+; CHECK-NEXT:    [[TMP3:%.*]] = and i32 [[TMP2]], 1
+; CHECK-NEXT:    ret i32 [[TMP3]]
 ;
   %2 = and i32 %0, 1
   %3 = icmp eq i32 %2, 0
@@ -25,12 +22,9 @@
 
 define <2 x i32> @f_m2_vec(<2 x i32>) {
 ; CHECK-LABEL: @f_m2_vec(
-; CHECK-NEXT:    [[TMP2:%.*]] = and <2 x i32> [[TMP0:%.*]], <i32 1, i32 1>
-; CHECK-NEXT:    [[TMP3:%.*]] = icmp eq <2 x i32> [[TMP2]], zeroinitializer
-; CHECK-NEXT:    [[TMP4:%.*]] = lshr <2 x i32> [[TMP0]], <i32 1, i32 1>
-; CHECK-NEXT:    [[TMP5:%.*]] = and <2 x i32> [[TMP4]], <i32 1, i32 1>
-; CHECK-NEXT:    [[TMP6:%.*]] = select <2 x i1> [[TMP3]], <2 x i32> [[TMP5]], <2 x i32> <i32 1, i32 1>
-; CHECK-NEXT:    ret <2 x i32> [[TMP6]]
+; CHECK-NEXT:    [[TMP2:%.*]] = lshr <2 x i32> [[TMP0:%.*]], <i32 1, i32 1>
+; CHECK-NEXT:    [[TMP3:%.*]] = and <2 x i32> [[TMP2]], <i32 1, i32 1>
+; CHECK-NEXT:    ret <2 x i32> [[TMP3]]
 ;
   %2 = and <2 x i32> %0, <i32 1, i32 1>
   %3 = icmp eq <2 x i32> %2, <i32 0, i32 0>
@@ -59,11 +53,10 @@
 
 define i32 @f_m3(i32) {
 ; CHECK-LABEL: @f_m3(
-; CHECK-NEXT:    [[TMP2:%.*]] = and i32 [[TMP0:%.*]], 2
-; CHECK-NEXT:    [[TMP3:%.*]] = icmp eq i32 [[TMP2]], 0
-; CHECK-NEXT:    [[TMP4:%.*]] = and i32 [[TMP0]], 1
-; CHECK-NEXT:    [[TMP5:%.*]] = select i1 [[TMP3]], i32 [[TMP4]], i32 1
-; CHECK-NEXT:    ret i32 [[TMP5]]
+; CHECK-NEXT:    [[TMP2:%.*]] = and i32 [[TMP0:%.*]], 3
+; CHECK-NEXT:    [[TMP3:%.*]] = icmp ne i32 [[TMP2]], 0
+; CHECK-NEXT:    [[TMP4:%.*]] = zext i1 [[TMP3]] to i32
+; CHECK-NEXT:    ret i32 [[TMP4]]
 ;
   %2 = and i32 %0, 2
   %3 = icmp eq i32 %2, 0
@@ -74,11 +67,10 @@
 
 define <2 x i32> @f_m3_vec(<2 x i32>) {
 ; CHECK-LABEL: @f_m3_vec(
-; CHECK-NEXT:    [[TMP2:%.*]] = and <2 x i32> [[TMP0:%.*]], <i32 2, i32 2>
-; CHECK-NEXT:    [[TMP3:%.*]] = icmp eq <2 x i32> [[TMP2]], zeroinitializer
-; CHECK-NEXT:    [[TMP4:%.*]] = and <2 x i32> [[TMP0]], <i32 1, i32 1>
-; CHECK-NEXT:    [[TMP5:%.*]] = select <2 x i1> [[TMP3]], <2 x i32> [[TMP4]], <2 x i32> <i32 1, i32 1>
-; CHECK-NEXT:    ret <2 x i32> [[TMP5]]
+; CHECK-NEXT:    [[TMP2:%.*]] = and <2 x i32> [[TMP0:%.*]], <i32 3, i32 3>
+; CHECK-NEXT:    [[TMP3:%.*]] = icmp ne <2 x i32> [[TMP2]], zeroinitializer
+; CHECK-NEXT:    [[TMP4:%.*]] = zext <2 x i1> [[TMP3]] to <2 x i32>
+; CHECK-NEXT:    ret <2 x i32> [[TMP4]]
 ;
   %2 = and <2 x i32> %0, <i32 2, i32 2>
   %3 = icmp eq <2 x i32> %2, <i32 0, i32 0>
@@ -104,12 +96,10 @@
 
 define i32 @f_m6(i32) {
 ; CHECK-LABEL: @f_m6(
-; CHECK-NEXT:    [[TMP2:%.*]] = and i32 [[TMP0:%.*]], 3
-; CHECK-NEXT:    [[TMP3:%.*]] = icmp eq i32 [[TMP2]], 0
-; CHECK-NEXT:    [[TMP4:%.*]] = lshr i32 [[TMP0]], 1
-; CHECK-NEXT:    [[TMP5:%.*]] = and i32 [[TMP4]], 1
-; CHECK-NEXT:    [[TMP6:%.*]] = select i1 [[TMP3]], i32 [[TMP5]], i32 1
-; CHECK-NEXT:    ret i32 [[TMP6]]
+; CHECK-NEXT:    [[TMP2:%.*]] = and i32 [[TMP0:%.*]], 6
+; CHECK-NEXT:    [[TMP3:%.*]] = icmp ne i32 [[TMP2]], 0
+; CHECK-NEXT:    [[TMP4:%.*]] = zext i1 [[TMP3]] to i32
+; CHECK-NEXT:    ret i32 [[TMP4]]
 ;
   %2 = and i32 %0, 3
   %3 = icmp eq i32 %2, 0
@@ -121,12 +111,10 @@
 
 define i32 @f_m10(i32) {
 ; CHECK-LABEL: @f_m10(
-; CHECK-NEXT:    [[TMP2:%.*]] = and i32 [[TMP0:%.*]], 4
-; CHECK-NEXT:    [[TMP3:%.*]] = icmp eq i32 [[TMP2]], 0
-; CHECK-NEXT:    [[TMP4:%.*]] = lshr i32 [[TMP0]], 1
-; CHECK-NEXT:    [[TMP5:%.*]] = and i32 [[TMP4]], 1
-; CHECK-NEXT:    [[TMP6:%.*]] = select i1 [[TMP3]], i32 [[TMP5]], i32 1
-; CHECK-NEXT:    ret i32 [[TMP6]]
+; CHECK-NEXT:    [[TMP2:%.*]] = and i32 [[TMP0:%.*]], 10
+; CHECK-NEXT:    [[TMP3:%.*]] = icmp ne i32 [[TMP2]], 0
+; CHECK-NEXT:    [[TMP4:%.*]] = zext i1 [[TMP3]] to i32
+; CHECK-NEXT:    ret i32 [[TMP4]]
 ;
   %2 = and i32 %0, 4
   %3 = icmp eq i32 %2, 0
@@ -138,12 +126,10 @@
 
 define i32 @f_m12(i32) {
 ; CHECK-LABEL: @f_m12(
-; CHECK-NEXT:    [[TMP2:%.*]] = and i32 [[TMP0:%.*]], 2
-; CHECK-NEXT:    [[TMP3:%.*]] = icmp eq i32 [[TMP2]], 0
-; CHECK-NEXT:    [[TMP4:%.*]] = lshr i32 [[TMP0]], 2
-; CHECK-NEXT:    [[TMP5:%.*]] = and i32 [[TMP4]], 1
-; CHECK-NEXT:    [[TMP6:%.*]] = select i1 [[TMP3]], i32 [[TMP5]], i32 1
-; CHECK-NEXT:    ret i32 [[TMP6]]
+; CHECK-NEXT:    [[TMP2:%.*]] = and i32 [[TMP0:%.*]], 12
+; CHECK-NEXT:    [[TMP3:%.*]] = icmp ne i32 [[TMP2]], 0
+; CHECK-NEXT:    [[TMP4:%.*]] = zext i1 [[TMP3]] to i32
+; CHECK-NEXT:    ret i32 [[TMP4]]
 ;
   %2 = and i32 %0, 2
   %3 = icmp eq i32 %2, 0