diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
index 8d9ebe4572315b..7b3c503facf18e 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -377,29 +377,31 @@ static bool canEvaluateTruncated(Value *V, Type *Ty, InstCombiner &IC,
     break;
   }
   case Instruction::Shl: {
-    // If we are truncating the result of this SHL, and if it's a shift of a
-    // constant amount, we can always perform a SHL in a smaller type.
-    const APInt *Amt;
-    if (match(I->getOperand(1), m_APInt(Amt))) {
-      uint32_t BitWidth = Ty->getScalarSizeInBits();
-      if (Amt->getLimitedValue(BitWidth) < BitWidth)
-        return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI);
-    }
+    // If we are truncating the result of this SHL, and if it's a shift of an
+    // inrange amount, we can always perform a SHL in a smaller type.
+    uint32_t BitWidth = Ty->getScalarSizeInBits();
+    KnownBits AmtKnownBits =
+        llvm::computeKnownBits(I->getOperand(1), IC.getDataLayout());
+    if (AmtKnownBits.getMaxValue().ult(BitWidth))
+      return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI) &&
+             canEvaluateTruncated(I->getOperand(1), Ty, IC, CxtI);
     break;
   }
   case Instruction::LShr: {
     // If this is a truncate of a logical shr, we can truncate it to a smaller
     // lshr iff we know that the bits we would otherwise be shifting in are
     // already zeros.
-    const APInt *Amt;
-    if (match(I->getOperand(1), m_APInt(Amt))) {
-      uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
-      uint32_t BitWidth = Ty->getScalarSizeInBits();
-      if (Amt->getLimitedValue(BitWidth) < BitWidth &&
-          IC.MaskedValueIsZero(I->getOperand(0),
-            APInt::getBitsSetFrom(OrigBitWidth, BitWidth), 0, CxtI)) {
-        return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI);
-      }
+    // TODO: It is enough to check that the bits we would be shifting in are
+    //       zero - use AmtKnownBits.getMaxValue().
+    uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
+    uint32_t BitWidth = Ty->getScalarSizeInBits();
+    KnownBits AmtKnownBits =
+        llvm::computeKnownBits(I->getOperand(1), IC.getDataLayout());
+    APInt ShiftedBits = APInt::getBitsSetFrom(OrigBitWidth, BitWidth);
+    if (AmtKnownBits.getMaxValue().ult(BitWidth) &&
+        IC.MaskedValueIsZero(I->getOperand(0), ShiftedBits, 0, CxtI)) {
+      return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI) &&
+             canEvaluateTruncated(I->getOperand(1), Ty, IC, CxtI);
     }
     break;
   }
@@ -409,15 +411,15 @@ static bool canEvaluateTruncated(Value *V, Type *Ty, InstCombiner &IC,
     // original type and the sign bit of the truncate type are similar.
     // TODO: It is enough to check that the bits we would be shifting in are
     //       similar to sign bit of the truncate type.
-    const APInt *Amt;
-    if (match(I->getOperand(1), m_APInt(Amt))) {
-      uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
-      uint32_t BitWidth = Ty->getScalarSizeInBits();
-      if (Amt->getLimitedValue(BitWidth) < BitWidth &&
-          OrigBitWidth - BitWidth <
-              IC.ComputeNumSignBits(I->getOperand(0), 0, CxtI))
-        return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI);
-    }
+    uint32_t OrigBitWidth = OrigTy->getScalarSizeInBits();
+    uint32_t BitWidth = Ty->getScalarSizeInBits();
+    KnownBits AmtKnownBits =
+        llvm::computeKnownBits(I->getOperand(1), IC.getDataLayout());
+    unsigned ShiftedBits = OrigBitWidth - BitWidth;
+    if (AmtKnownBits.getMaxValue().ult(BitWidth) &&
+        ShiftedBits < IC.ComputeNumSignBits(I->getOperand(0), 0, CxtI))
+      return canEvaluateTruncated(I->getOperand(0), Ty, IC, CxtI) &&
+             canEvaluateTruncated(I->getOperand(1), Ty, IC, CxtI);
     break;
   }
   case Instruction::Trunc:
diff --git a/llvm/test/Transforms/InstCombine/2008-01-21-MulTrunc.ll b/llvm/test/Transforms/InstCombine/2008-01-21-MulTrunc.ll
index 999b5d58f43898..89e4a3c1aaed63 100644
--- a/llvm/test/Transforms/InstCombine/2008-01-21-MulTrunc.ll
+++ b/llvm/test/Transforms/InstCombine/2008-01-21-MulTrunc.ll
@@ -35,12 +35,10 @@ define <2 x i16> @test1_vec(<2 x i16> %a) {
 
 define <2 x i16> @test1_vec_nonuniform(<2 x i16> %a) {
 ; CHECK-LABEL: @test1_vec_nonuniform(
-; CHECK-NEXT:    [[B:%.*]] = zext <2 x i16> [[A:%.*]] to <2 x i32>
-; CHECK-NEXT:    [[C:%.*]] = lshr <2 x i32> [[B]], <i32 8, i32 9>
-; CHECK-NEXT:    [[D:%.*]] = mul nuw nsw <2 x i32> [[B]], <i32 5, i32 6>
-; CHECK-NEXT:    [[E:%.*]] = or <2 x i32> [[C]], [[D]]
-; CHECK-NEXT:    [[F:%.*]] = trunc <2 x i32> [[E]] to <2 x i16>
-; CHECK-NEXT:    ret <2 x i16> [[F]]
+; CHECK-NEXT:    [[C:%.*]] = lshr <2 x i16> [[A:%.*]], <i16 8, i16 9>
+; CHECK-NEXT:    [[D:%.*]] = mul <2 x i16> [[A]], <i16 5, i16 6>
+; CHECK-NEXT:    [[E:%.*]] = or <2 x i16> [[C]], [[D]]
+; CHECK-NEXT:    ret <2 x i16> [[E]]
 ;
   %b = zext <2 x i16> %a to <2 x i32>
   %c = lshr <2 x i32> %b, <i32 8, i32 9>
diff --git a/llvm/test/Transforms/InstCombine/cast.ll b/llvm/test/Transforms/InstCombine/cast.ll
index 10d59bfff57f47..18b411103122c0 100644
--- a/llvm/test/Transforms/InstCombine/cast.ll
+++ b/llvm/test/Transforms/InstCombine/cast.ll
@@ -502,12 +502,10 @@ define <2 x i16> @test40vec(<2 x i16> %a) {
 
 define <2 x i16> @test40vec_nonuniform(<2 x i16> %a) {
 ; ALL-LABEL: @test40vec_nonuniform(
-; ALL-NEXT:    [[T:%.*]] = zext <2 x i16> [[A:%.*]] to <2 x i32>
-; ALL-NEXT:    [[T21:%.*]] = lshr <2 x i32> [[T]], <i32 9, i32 10>
-; ALL-NEXT:    [[T5:%.*]] = shl <2 x i32> [[T]], <i32 8, i32 9>
-; ALL-NEXT:    [[T32:%.*]] = or <2 x i32> [[T21]], [[T5]]
-; ALL-NEXT:    [[R:%.*]] = trunc <2 x i32> [[T32]] to <2 x i16>
-; ALL-NEXT:    ret <2 x i16> [[R]]
+; ALL-NEXT:    [[T21:%.*]] = lshr <2 x i16> [[A:%.*]], <i16 9, i16 10>
+; ALL-NEXT:    [[T5:%.*]] = shl <2 x i16> [[A]], <i16 8, i16 9>
+; ALL-NEXT:    [[T32:%.*]] = or <2 x i16> [[T21]], [[T5]]
+; ALL-NEXT:    ret <2 x i16> [[T32]]
 ;
   %t = zext <2 x i16> %a to <2 x i32>
   %t21 = lshr <2 x i32> %t, <i32 9, i32 10>
diff --git a/llvm/test/Transforms/InstCombine/trunc.ll b/llvm/test/Transforms/InstCombine/trunc.ll
index 4e9f440978a59b..d8a615cc4c9a38 100644
--- a/llvm/test/Transforms/InstCombine/trunc.ll
+++ b/llvm/test/Transforms/InstCombine/trunc.ll
@@ -286,12 +286,11 @@ define <2 x i64> @test8_vec(<2 x i32> %A, <2 x i32> %B) {
 
 define <2 x i64> @test8_vec_nonuniform(<2 x i32> %A, <2 x i32> %B) {
 ; CHECK-LABEL: @test8_vec_nonuniform(
-; CHECK-NEXT:    [[C:%.*]] = zext <2 x i32> [[A:%.*]] to <2 x i128>
-; CHECK-NEXT:    [[D:%.*]] = zext <2 x i32> [[B:%.*]] to <2 x i128>
-; CHECK-NEXT:    [[E:%.*]] = shl <2 x i128> [[D]], <i128 32, i128 48>
-; CHECK-NEXT:    [[F:%.*]] = or <2 x i128> [[E]], [[C]]
-; CHECK-NEXT:    [[G:%.*]] = trunc <2 x i128> [[F]] to <2 x i64>
-; CHECK-NEXT:    ret <2 x i64> [[G]]
+; CHECK-NEXT:    [[C:%.*]] = zext <2 x i32> [[A:%.*]] to <2 x i64>
+; CHECK-NEXT:    [[D:%.*]] = zext <2 x i32> [[B:%.*]] to <2 x i64>
+; CHECK-NEXT:    [[E:%.*]] = shl <2 x i64> [[D]], <i64 32, i64 48>
+; CHECK-NEXT:    [[F:%.*]] = or <2 x i64> [[E]], [[C]]
+; CHECK-NEXT:    ret <2 x i64> [[F]]
 ;
   %C = zext <2 x i32> %A to <2 x i128>
   %D = zext <2 x i32> %B to <2 x i128>
@@ -343,12 +342,11 @@ define i8 @test10(i32 %X) {
 
 define i64 @test11(i32 %A, i32 %B) {
 ; CHECK-LABEL: @test11(
-; CHECK-NEXT:    [[C:%.*]] = zext i32 [[A:%.*]] to i128
+; CHECK-NEXT:    [[C:%.*]] = zext i32 [[A:%.*]] to i64
 ; CHECK-NEXT:    [[TMP1:%.*]] = and i32 [[B:%.*]], 31
-; CHECK-NEXT:    [[E:%.*]] = zext i32 [[TMP1]] to i128
-; CHECK-NEXT:    [[F:%.*]] = shl i128 [[C]], [[E]]
-; CHECK-NEXT:    [[G:%.*]] = trunc i128 [[F]] to i64
-; CHECK-NEXT:    ret i64 [[G]]
+; CHECK-NEXT:    [[E:%.*]] = zext i32 [[TMP1]] to i64
+; CHECK-NEXT:    [[F:%.*]] = shl i64 [[C]], [[E]]
+; CHECK-NEXT:    ret i64 [[F]]
 ;
   %C = zext i32 %A to i128
   %D = zext i32 %B to i128
@@ -360,12 +358,11 @@ define i64 @test11(i32 %A, i32 %B) {
 
 define <2 x i64> @test11_vec(<2 x i32> %A, <2 x i32> %B) {
 ; CHECK-LABEL: @test11_vec(
-; CHECK-NEXT:    [[C:%.*]] = zext <2 x i32> [[A:%.*]] to <2 x i128>
+; CHECK-NEXT:    [[C:%.*]] = zext <2 x i32> [[A:%.*]] to <2 x i64>
 ; CHECK-NEXT:    [[TMP1:%.*]] = and <2 x i32> [[B:%.*]], <i32 31, i32 31>
-; CHECK-NEXT:    [[E:%.*]] = zext <2 x i32> [[TMP1]] to <2 x i128>
-; CHECK-NEXT:    [[F:%.*]] = shl <2 x i128> [[C]], [[E]]
-; CHECK-NEXT:    [[G:%.*]] = trunc <2 x i128> [[F]] to <2 x i64>
-; CHECK-NEXT:    ret <2 x i64> [[G]]
+; CHECK-NEXT:    [[E:%.*]] = zext <2 x i32> [[TMP1]] to <2 x i64>
+; CHECK-NEXT:    [[F:%.*]] = shl <2 x i64> [[C]], [[E]]
+; CHECK-NEXT:    ret <2 x i64> [[F]]
 ;
   %C = zext <2 x i32> %A to <2 x i128>
   %D = zext <2 x i32> %B to <2 x i128>
@@ -377,12 +374,11 @@ define <2 x i64> @test11_vec(<2 x i32> %A, <2 x i32> %B) {
 
 define <2 x i64> @test11_vec_nonuniform(<2 x i32> %A, <2 x i32> %B) {
 ; CHECK-LABEL: @test11_vec_nonuniform(
-; CHECK-NEXT:    [[C:%.*]] = zext <2 x i32> [[A:%.*]] to <2 x i128>
+; CHECK-NEXT:    [[C:%.*]] = zext <2 x i32> [[A:%.*]] to <2 x i64>
 ; CHECK-NEXT:    [[TMP1:%.*]] = and <2 x i32> [[B:%.*]], <i32 31, i32 15>
-; CHECK-NEXT:    [[E:%.*]] = zext <2 x i32> [[TMP1]] to <2 x i128>
-; CHECK-NEXT:    [[F:%.*]] = shl <2 x i128> [[C]], [[E]]
-; CHECK-NEXT:    [[G:%.*]] = trunc <2 x i128> [[F]] to <2 x i64>
-; CHECK-NEXT:    ret <2 x i64> [[G]]
+; CHECK-NEXT:    [[E:%.*]] = zext <2 x i32> [[TMP1]] to <2 x i64>
+; CHECK-NEXT:    [[F:%.*]] = shl <2 x i64> [[C]], [[E]]
+; CHECK-NEXT:    ret <2 x i64> [[F]]
 ;
   %C = zext <2 x i32> %A to <2 x i128>
   %D = zext <2 x i32> %B to <2 x i128>
@@ -411,12 +407,11 @@ define <2 x i64> @test11_vec_undef(<2 x i32> %A, <2 x i32> %B) {
 
 define i64 @test12(i32 %A, i32 %B) {
 ; CHECK-LABEL: @test12(
-; CHECK-NEXT:    [[C:%.*]] = zext i32 [[A:%.*]] to i128
+; CHECK-NEXT:    [[C:%.*]] = zext i32 [[A:%.*]] to i64
 ; CHECK-NEXT:    [[TMP1:%.*]] = and i32 [[B:%.*]], 31
-; CHECK-NEXT:    [[E:%.*]] = zext i32 [[TMP1]] to i128
-; CHECK-NEXT:    [[F:%.*]] = lshr i128 [[C]], [[E]]
-; CHECK-NEXT:    [[G:%.*]] = trunc i128 [[F]] to i64
-; CHECK-NEXT:    ret i64 [[G]]
+; CHECK-NEXT:    [[E:%.*]] = zext i32 [[TMP1]] to i64
+; CHECK-NEXT:    [[F:%.*]] = lshr i64 [[C]], [[E]]
+; CHECK-NEXT:    ret i64 [[F]]
 ;
   %C = zext i32 %A to i128
   %D = zext i32 %B to i128
@@ -428,12 +423,11 @@ define i64 @test12(i32 %A, i32 %B) {
 
 define <2 x i64> @test12_vec(<2 x i32> %A, <2 x i32> %B) {
 ; CHECK-LABEL: @test12_vec(
-; CHECK-NEXT:    [[C:%.*]] = zext <2 x i32> [[A:%.*]] to <2 x i128>
+; CHECK-NEXT:    [[C:%.*]] = zext <2 x i32> [[A:%.*]] to <2 x i64>
 ; CHECK-NEXT:    [[TMP1:%.*]] = and <2 x i32> [[B:%.*]], <i32 31, i32 31>
-; CHECK-NEXT:    [[E:%.*]] = zext <2 x i32> [[TMP1]] to <2 x i128>
-; CHECK-NEXT:    [[F:%.*]] = lshr <2 x i128> [[C]], [[E]]
-; CHECK-NEXT:    [[G:%.*]] = trunc <2 x i128> [[F]] to <2 x i64>
-; CHECK-NEXT:    ret <2 x i64> [[G]]
+; CHECK-NEXT:    [[E:%.*]] = zext <2 x i32> [[TMP1]] to <2 x i64>
+; CHECK-NEXT:    [[F:%.*]] = lshr <2 x i64> [[C]], [[E]]
+; CHECK-NEXT:    ret <2 x i64> [[F]]
 ;
   %C = zext <2 x i32> %A to <2 x i128>
   %D = zext <2 x i32> %B to <2 x i128>
@@ -445,12 +439,11 @@ define <2 x i64> @test12_vec(<2 x i32> %A, <2 x i32> %B) {
 
 define <2 x i64> @test12_vec_nonuniform(<2 x i32> %A, <2 x i32> %B) {
 ; CHECK-LABEL: @test12_vec_nonuniform(
-; CHECK-NEXT:    [[C:%.*]] = zext <2 x i32> [[A:%.*]] to <2 x i128>
+; CHECK-NEXT:    [[C:%.*]] = zext <2 x i32> [[A:%.*]] to <2 x i64>
 ; CHECK-NEXT:    [[TMP1:%.*]] = and <2 x i32> [[B:%.*]], <i32 31, i32 15>
-; CHECK-NEXT:    [[E:%.*]] = zext <2 x i32> [[TMP1]] to <2 x i128>
-; CHECK-NEXT:    [[F:%.*]] = lshr <2 x i128> [[C]], [[E]]
-; CHECK-NEXT:    [[G:%.*]] = trunc <2 x i128> [[F]] to <2 x i64>
-; CHECK-NEXT:    ret <2 x i64> [[G]]
+; CHECK-NEXT:    [[E:%.*]] = zext <2 x i32> [[TMP1]] to <2 x i64>
+; CHECK-NEXT:    [[F:%.*]] = lshr <2 x i64> [[C]], [[E]]
+; CHECK-NEXT:    ret <2 x i64> [[F]]
 ;
   %C = zext <2 x i32> %A to <2 x i128>
   %D = zext <2 x i32> %B to <2 x i128>
@@ -479,12 +472,11 @@ define <2 x i64> @test12_vec_undef(<2 x i32> %A, <2 x i32> %B) {
 
 define i64 @test13(i32 %A, i32 %B) {
 ; CHECK-LABEL: @test13(
-; CHECK-NEXT:    [[C:%.*]] = sext i32 [[A:%.*]] to i128
+; CHECK-NEXT:    [[C:%.*]] = sext i32 [[A:%.*]] to i64
 ; CHECK-NEXT:    [[TMP1:%.*]] = and i32 [[B:%.*]], 31
-; CHECK-NEXT:    [[E:%.*]] = zext i32 [[TMP1]] to i128
-; CHECK-NEXT:    [[F:%.*]] = ashr i128 [[C]], [[E]]
-; CHECK-NEXT:    [[G:%.*]] = trunc i128 [[F]] to i64
-; CHECK-NEXT:    ret i64 [[G]]
+; CHECK-NEXT:    [[E:%.*]] = zext i32 [[TMP1]] to i64
+; CHECK-NEXT:    [[F:%.*]] = ashr i64 [[C]], [[E]]
+; CHECK-NEXT:    ret i64 [[F]]
 ;
   %C = sext i32 %A to i128
   %D = zext i32 %B to i128
@@ -496,12 +488,11 @@ define i64 @test13(i32 %A, i32 %B) {
 
 define <2 x i64> @test13_vec(<2 x i32> %A, <2 x i32> %B) {
 ; CHECK-LABEL: @test13_vec(
-; CHECK-NEXT:    [[C:%.*]] = sext <2 x i32> [[A:%.*]] to <2 x i128>
+; CHECK-NEXT:    [[C:%.*]] = sext <2 x i32> [[A:%.*]] to <2 x i64>
 ; CHECK-NEXT:    [[TMP1:%.*]] = and <2 x i32> [[B:%.*]], <i32 31, i32 31>
-; CHECK-NEXT:    [[E:%.*]] = zext <2 x i32> [[TMP1]] to <2 x i128>
-; CHECK-NEXT:    [[F:%.*]] = ashr <2 x i128> [[C]], [[E]]
-; CHECK-NEXT:    [[G:%.*]] = trunc <2 x i128> [[F]] to <2 x i64>
-; CHECK-NEXT:    ret <2 x i64> [[G]]
+; CHECK-NEXT:    [[E:%.*]] = zext <2 x i32> [[TMP1]] to <2 x i64>
+; CHECK-NEXT:    [[F:%.*]] = ashr <2 x i64> [[C]], [[E]]
+; CHECK-NEXT:    ret <2 x i64> [[F]]
 ;
   %C = sext <2 x i32> %A to <2 x i128>
   %D = zext <2 x i32> %B to <2 x i128>
@@ -513,12 +504,11 @@ define <2 x i64> @test13_vec(<2 x i32> %A, <2 x i32> %B) {
 
 define <2 x i64> @test13_vec_nonuniform(<2 x i32> %A, <2 x i32> %B) {
 ; CHECK-LABEL: @test13_vec_nonuniform(
-; CHECK-NEXT:    [[C:%.*]] = sext <2 x i32> [[A:%.*]] to <2 x i128>
+; CHECK-NEXT:    [[C:%.*]] = sext <2 x i32> [[A:%.*]] to <2 x i64>
 ; CHECK-NEXT:    [[TMP1:%.*]] = and <2 x i32> [[B:%.*]], <i32 31, i32 15>
-; CHECK-NEXT:    [[E:%.*]] = zext <2 x i32> [[TMP1]] to <2 x i128>
-; CHECK-NEXT:    [[F:%.*]] = ashr <2 x i128> [[C]], [[E]]
-; CHECK-NEXT:    [[G:%.*]] = trunc <2 x i128> [[F]] to <2 x i64>
-; CHECK-NEXT:    ret <2 x i64> [[G]]
+; CHECK-NEXT:    [[E:%.*]] = zext <2 x i32> [[TMP1]] to <2 x i64>
+; CHECK-NEXT:    [[F:%.*]] = ashr <2 x i64> [[C]], [[E]]
+; CHECK-NEXT:    ret <2 x i64> [[F]]
 ;
   %C = sext <2 x i32> %A to <2 x i128>
   %D = zext <2 x i32> %B to <2 x i128>