Index: llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -1289,8 +1289,8 @@
 // Iff -C1 s<= C2 s<= C0-C1
 // Also ULT predicate can also be UGT iff C0 != -1 (+invert result)
 //      SLT predicate can also be SGT iff C2 != INT_MAX (+invert res.)
-static Instruction *canonicalizeClampLike(SelectInst &Sel0, ICmpInst &Cmp0,
-                                          InstCombiner::BuilderTy &Builder) {
+static Value *canonicalizeClampLike(SelectInst &Sel0, ICmpInst &Cmp0,
+                                    InstCombiner::BuilderTy &Builder) {
   Value *X = Sel0.getTrueValue();
   Value *Sel1 = Sel0.getFalseValue();
 
@@ -1337,6 +1337,12 @@
   if (!Sel1->hasOneUse())
     return nullptr;
 
+  // If the types do not match, look through any truncs to the underlying
+  // instruction.
+  if (Cmp00->getType() != X->getType())
+    if (auto *T = dyn_cast<TruncInst>(X))
+      X = T->getOperand(0);
+
   // We now can finish matching the condition of the outermost select:
   // it should either be the X itself, or an addition of some constant to X.
   Constant *C1;
@@ -1407,15 +1413,25 @@
   if (!match(Precond2, m_One()))
     return nullptr;
 
+  // If we are matching from a truncated input, we need to sext the
+  // ReplacementLow and ReplacementHigh values. Only do the transform if they
+  // are free to extend due to being constants.
+  if (X->getType() != Sel0.getType() &&
+      (!isa<Constant>(ReplacementLow) || !isa<Constant>(ReplacementHigh)))
+    return nullptr;
+
   // All good, finally emit the new pattern.
   Value *ShouldReplaceLow = Builder.CreateICmpSLT(X, ThresholdLowIncl);
   Value *ShouldReplaceHigh = Builder.CreateICmpSGE(X, ThresholdHighExcl);
-  Value *MaybeReplacedLow =
-      Builder.CreateSelect(ShouldReplaceLow, ReplacementLow, X);
-  Instruction *MaybeReplacedHigh =
-      SelectInst::Create(ShouldReplaceHigh, ReplacementHigh, MaybeReplacedLow);
-
-  return MaybeReplacedHigh;
+  Value *MaybeReplacedLow = Builder.CreateSelect(
+      ShouldReplaceLow, Builder.CreateSExt(ReplacementLow, X->getType()), X);
+
+  // Create the final select. If we looked through a truncate above, we will
+  // need to retruncate the result.
+  Value *MaybeReplacedHigh = Builder.CreateSelect(
+      ShouldReplaceHigh, Builder.CreateSExt(ReplacementHigh, X->getType()),
+      MaybeReplacedLow);
+  return Builder.CreateTrunc(MaybeReplacedHigh, Sel0.getType());
 }
 
 // If we have
@@ -1506,8 +1522,8 @@
   if (Instruction *NewAbs = canonicalizeAbsNabs(SI, *ICI, *this))
     return NewAbs;
 
-  if (Instruction *NewAbs = canonicalizeClampLike(SI, *ICI, Builder))
-    return NewAbs;
+  if (Value *V = canonicalizeClampLike(SI, *ICI, Builder))
+    return replaceInstUsesWith(SI, V);
 
   if (Instruction *NewSel =
           tryToReuseConstantFromSelectInComparison(SI, *ICI, *this))
Index: llvm/test/Transforms/InstCombine/truncating-saturate.ll
===================================================================
--- llvm/test/Transforms/InstCombine/truncating-saturate.ll
+++ llvm/test/Transforms/InstCombine/truncating-saturate.ll
@@ -57,13 +57,12 @@
 
 define i16 @testi32i16i8(i32 %add) {
 ; CHECK-LABEL: @testi32i16i8(
-; CHECK-NEXT:    [[A:%.*]] = add i32 [[ADD:%.*]], 128
-; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i32 [[A]], 256
-; CHECK-NEXT:    [[T:%.*]] = trunc i32 [[ADD]] to i16
-; CHECK-NEXT:    [[C:%.*]] = icmp sgt i32 [[ADD]], -1
-; CHECK-NEXT:    [[F:%.*]] = select i1 [[C]], i16 127, i16 -128
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[CMP]], i16 [[T]], i16 [[F]]
-; CHECK-NEXT:    ret i16 [[R]]
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp sgt i32 [[ADD:%.*]], -128
+; CHECK-NEXT:    [[TMP2:%.*]] = select i1 [[TMP1]], i32 [[ADD]], i32 -128
+; CHECK-NEXT:    [[TMP3:%.*]] = icmp slt i32 [[TMP2]], 127
+; CHECK-NEXT:    [[TMP4:%.*]] = select i1 [[TMP3]], i32 [[TMP2]], i32 127
+; CHECK-NEXT:    [[TMP5:%.*]] = trunc i32 [[TMP4]] to i16
+; CHECK-NEXT:    ret i16 [[TMP5]]
 ;
   %a = add i32 %add, 128
   %cmp = icmp ult i32 %a, 256
@@ -76,13 +75,12 @@
 
 define <4 x i16> @testv4i32i16i8(<4 x i32> %add) {
 ; CHECK-LABEL: @testv4i32i16i8(
-; CHECK-NEXT:    [[A:%.*]] = add <4 x i32> [[ADD:%.*]], <i32 128, i32 128, i32 128, i32 128>
-; CHECK-NEXT:    [[CMP:%.*]] = icmp ult <4 x i32> [[A]], <i32 256, i32 256, i32 256, i32 256>
-; CHECK-NEXT:    [[T:%.*]] = trunc <4 x i32> [[ADD]] to <4 x i16>
-; CHECK-NEXT:    [[C:%.*]] = icmp sgt <4 x i32> [[ADD]], <i32 -1, i32 -1, i32 -1, i32 -1>
-; CHECK-NEXT:    [[F:%.*]] = select <4 x i1> [[C]], <4 x i16> <i16 127, i16 127, i16 127, i16 127>, <4 x i16> <i16 -128, i16 -128, i16 -128, i16 -128>
-; CHECK-NEXT:    [[R:%.*]] = select <4 x i1> [[CMP]], <4 x i16> [[T]], <4 x i16> [[F]]
-; CHECK-NEXT:    ret <4 x i16> [[R]]
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp sgt <4 x i32> [[ADD:%.*]], <i32 -128, i32 -128, i32 -128, i32 -128>
+; CHECK-NEXT:    [[TMP2:%.*]] = select <4 x i1> [[TMP1]], <4 x i32> [[ADD]], <4 x i32> <i32 -128, i32 -128, i32 -128, i32 -128>
+; CHECK-NEXT:    [[TMP3:%.*]] = icmp slt <4 x i32> [[TMP2]], <i32 127, i32 127, i32 127, i32 127>
+; CHECK-NEXT:    [[TMP4:%.*]] = select <4 x i1> [[TMP3]], <4 x i32> [[TMP2]], <4 x i32> <i32 127, i32 127, i32 127, i32 127>
+; CHECK-NEXT:    [[TMP5:%.*]] = trunc <4 x i32> [[TMP4]] to <4 x i16>
+; CHECK-NEXT:    ret <4 x i16> [[TMP5]]
 ;
   %a = add <4 x i32> %add, <i32 128, i32 128, i32 128, i32 128>
   %cmp = icmp ult <4 x i32> %a, <i32 256, i32 256, i32 256, i32 256>
@@ -98,8 +96,8 @@
 ; CHECK-NEXT:    [[TMP1:%.*]] = icmp sgt i32 [[ADD:%.*]], -128
 ; CHECK-NEXT:    [[TMP2:%.*]] = select i1 [[TMP1]], i32 [[ADD]], i32 -128
 ; CHECK-NEXT:    [[TMP3:%.*]] = icmp slt i32 [[TMP2]], 127
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[TMP3]], i32 [[TMP2]], i32 127
-; CHECK-NEXT:    ret i32 [[R]]
+; CHECK-NEXT:    [[TMP4:%.*]] = select i1 [[TMP3]], i32 [[TMP2]], i32 127
+; CHECK-NEXT:    ret i32 [[TMP4]]
 ;
   %a = add i32 %add, 128
   %cmp = icmp ult i32 %a, 256
@@ -115,8 +113,8 @@
 ; CHECK-NEXT:    [[TMP1:%.*]] = icmp sgt i16 [[T]], -128
 ; CHECK-NEXT:    [[TMP2:%.*]] = select i1 [[TMP1]], i16 [[T]], i16 -128
 ; CHECK-NEXT:    [[TMP3:%.*]] = icmp slt i16 [[TMP2]], 127
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[TMP3]], i16 [[TMP2]], i16 127
-; CHECK-NEXT:    ret i16 [[R]]
+; CHECK-NEXT:    [[TMP4:%.*]] = select i1 [[TMP3]], i16 [[TMP2]], i16 127
+; CHECK-NEXT:    ret i16 [[TMP4]]
 ;
   %t = trunc i32 %add to i16
   %a = add i16 %t, 128
@@ -310,13 +308,12 @@
 
 define i16 @differentconsts(i32 %x, i16 %replacement_low, i16 %replacement_high) {
 ; CHECK-LABEL: @differentconsts(
-; CHECK-NEXT:    [[T0:%.*]] = icmp slt i32 [[X:%.*]], 128
-; CHECK-NEXT:    [[T1:%.*]] = select i1 [[T0]], i16 256, i16 -1
-; CHECK-NEXT:    [[T2:%.*]] = add i32 [[X]], 16
-; CHECK-NEXT:    [[T3:%.*]] = icmp ult i32 [[T2]], 144
-; CHECK-NEXT:    [[T4:%.*]] = trunc i32 [[X]] to i16
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[T3]], i16 [[T4]], i16 [[T1]]
-; CHECK-NEXT:    ret i16 [[R]]
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp slt i32 [[X:%.*]], -16
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp sgt i32 [[X]], 127
+; CHECK-NEXT:    [[TMP3:%.*]] = trunc i32 [[X]] to i16
+; CHECK-NEXT:    [[TMP4:%.*]] = select i1 [[TMP1]], i16 256, i16 [[TMP3]]
+; CHECK-NEXT:    [[TMP5:%.*]] = select i1 [[TMP2]], i16 -1, i16 [[TMP4]]
+; CHECK-NEXT:    ret i16 [[TMP5]]
 ;
   %t0 = icmp slt i32 %x, 128
   %t1 = select i1 %t0, i16 256, i16 65535