Index: lib/Transforms/InstCombine/InstCombineCompares.cpp
===================================================================
--- lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -1932,11 +1932,20 @@
     }
   }
 
-  // If this is a signed comparison to 0 and the shift is sign preserving,
-  // use the shift LHS operand instead; isSignTest may change 'Pred', so only
-  // do that if we're sure to not continue on in this function.
-  if (Shl->hasNoSignedWrap() && isSignTest(Pred, *C))
-    return new ICmpInst(Pred, X, Constant::getNullValue(X->getType()));
+  if (Shl->hasNoSignedWrap()) {
+    // TODO: What other predicates (possibly with extra pre-conditions) can we
+    // handle here?
+    if (Pred == ICmpInst::ICMP_SGT) {
+      APInt ShiftedC = C->ashr(*ShiftAmt);
+      return new ICmpInst(Pred, X, ConstantInt::get(X->getType(), ShiftedC));
+    }
+
+    // If this is a signed comparison to 0 and the shift is sign preserving,
+    // use the shift LHS operand instead; isSignTest may change 'Pred', so only
+    // do that if we're sure to not continue on in this function.
+    if (isSignTest(Pred, *C))
+      return new ICmpInst(Pred, X, Constant::getNullValue(X->getType()));
+  }
 
   // Otherwise, if this is a comparison of the sign bit, simplify to and/test.
   bool TrueIfSigned = false;
Index: test/Transforms/InstCombine/icmp-shl-nsw.ll
===================================================================
--- test/Transforms/InstCombine/icmp-shl-nsw.ll
+++ test/Transforms/InstCombine/icmp-shl-nsw.ll
@@ -84,8 +84,7 @@
 
 define i1 @icmp_sgt2(i8 %x) {
 ; CHECK-LABEL: @icmp_sgt2(
-; CHECK-NEXT:    [[SHL:%.*]] = shl nsw i8 %x, 1
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 [[SHL]], -127
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 %x, -64
 ; CHECK-NEXT:    ret i1 [[CMP]]
 ;
   %shl = shl nsw i8 %x, 1
@@ -95,8 +94,7 @@
 
 define i1 @icmp_sgt3(i8 %x) {
 ; CHECK-LABEL: @icmp_sgt3(
-; CHECK-NEXT:    [[SHL:%.*]] = shl nsw i8 %x, 1
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 [[SHL]], -16
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 %x, -8
 ; CHECK-NEXT:    ret i1 [[CMP]]
 ;
   %shl = shl nsw i8 %x, 1
@@ -106,8 +104,7 @@
 
 define i1 @icmp_sgt4(i8 %x) {
 ; CHECK-LABEL: @icmp_sgt4(
-; CHECK-NEXT:    [[SHL:%.*]] = shl nsw i8 %x, 1
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 [[SHL]], -2
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 %x, -1
 ; CHECK-NEXT:    ret i1 [[CMP]]
 ;
   %shl = shl nsw i8 %x, 1
@@ -120,8 +117,7 @@
 
 define i1 @icmp_sgt5(i8 %x) {
 ; CHECK-LABEL: @icmp_sgt5(
-; CHECK-NEXT:    [[SHL:%.*]] = shl nsw i8 %x, 1
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 [[SHL]], 1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 %x, 0
 ; CHECK-NEXT:    ret i1 [[CMP]]
 ;
   %shl = shl nsw i8 %x, 1
@@ -131,8 +127,7 @@
 
 define i1 @icmp_sgt6(i8 %x) {
 ; CHECK-LABEL: @icmp_sgt6(
-; CHECK-NEXT:    [[SHL:%.*]] = shl nsw i8 %x, 1
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 [[SHL]], 16
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 %x, 8
 ; CHECK-NEXT:    ret i1 [[CMP]]
 ;
   %shl = shl nsw i8 %x, 1
@@ -142,8 +137,7 @@
 
 define i1 @icmp_sgt7(i8 %x) {
 ; CHECK-LABEL: @icmp_sgt7(
-; CHECK-NEXT:    [[SHL:%.*]] = shl nsw i8 %x, 1
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 [[SHL]], 124
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 %x, 62
 ; CHECK-NEXT:    ret i1 [[CMP]]
 ;
   %shl = shl nsw i8 %x, 1
@@ -181,8 +175,7 @@
 
 define i1 @icmp_sgt10(i8 %x) {
 ; CHECK-LABEL: @icmp_sgt10(
-; CHECK-NEXT:    [[SHL:%.*]] = shl nsw i8 %x, 7
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 [[SHL]], -127
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 %x, -1
 ; CHECK-NEXT:    ret i1 [[CMP]]
 ;
   %shl = shl nsw i8 %x, 7
@@ -192,8 +185,7 @@
 
 define i1 @icmp_sgt11(i8 %x) {
 ; CHECK-LABEL: @icmp_sgt11(
-; CHECK-NEXT:    [[SHL:%.*]] = shl nsw i8 %x, 7
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 [[SHL]], -2
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i8 %x, -1
 ; CHECK-NEXT:    ret i1 [[CMP]]
 ;
   %shl = shl nsw i8 %x, 7
@@ -205,8 +197,7 @@
 
 define <2 x i1> @icmp_sgt11_vec(<2 x i8> %x) {
 ; CHECK-LABEL: @icmp_sgt11_vec(
-; CHECK-NEXT:    [[SHL:%.*]] = shl nsw <2 x i8> %x, <i8 7, i8 7>
-; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt <2 x i8> [[SHL]], <i8 -2, i8 -2>
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt <2 x i8> %x, <i8 -1, i8 -1>
 ; CHECK-NEXT:    ret <2 x i1> [[CMP]]
 ;
   %shl = shl nsw <2 x i8> %x, <i8 7, i8 7>