diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
--- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -713,6 +713,25 @@
     return replaceInstUsesWith(Trunc, Res);
   }
 
+  // For integer types, check if we can shorten the entire input expression to
+  // DestWidth * 2, which won't allow removing the truncate, but reducing the
+  // width may enable further optimizations, e.g. allowing for larger
+  // vectorization factors.
+  if (auto *DestITy = dyn_cast<IntegerType>(DestTy)) {
+    if (DestWidth * 2 < SrcWidth) {
+      auto *NewDestTy = DestITy->getExtendedType();
+      if (shouldChangeType(SrcTy, DestTy) &&
+          canEvaluateTruncated(Src, NewDestTy, *this, &Trunc)) {
+        LLVM_DEBUG(
+            dbgs() << "ICE: EvaluateInDifferentType converting expression type"
+                      " to reduce the width of operand of"
+                   << Trunc << '\n');
+        Value *Res = EvaluateInDifferentType(Src, NewDestTy, false);
+        return new TruncInst(Res, DestTy);
+      }
+    }
+  }
+
   // Test if the trunc is the user of a select which is part of a
   // minimum or maximum operation. If so, don't do any more simplification.
   // Even simplifying demanded bits can break the canonical form of a
diff --git a/llvm/test/Transforms/InstCombine/trunc-binop-ext.ll b/llvm/test/Transforms/InstCombine/trunc-binop-ext.ll
--- a/llvm/test/Transforms/InstCombine/trunc-binop-ext.ll
+++ b/llvm/test/Transforms/InstCombine/trunc-binop-ext.ll
@@ -318,11 +318,11 @@
 ; Test cases for PR43580
 define i8 @narrow_zext_ashr_keep_trunc(i8 %i1, i8 %i2) {
 ; CHECK-LABEL: @narrow_zext_ashr_keep_trunc(
-; CHECK-NEXT:    [[I1_EXT:%.*]] = sext i8 [[I1:%.*]] to i32
-; CHECK-NEXT:    [[I2_EXT:%.*]] = sext i8 [[I2:%.*]] to i32
-; CHECK-NEXT:    [[SUB:%.*]] = add nsw i32 [[I1_EXT]], [[I2_EXT]]
-; CHECK-NEXT:    [[SHIFT:%.*]] = lshr i32 [[SUB]], 1
-; CHECK-NEXT:    [[T:%.*]] = trunc i32 [[SHIFT]] to i8
+; CHECK-NEXT:    [[I1_EXT:%.*]] = sext i8 [[I1:%.*]] to i16
+; CHECK-NEXT:    [[I2_EXT:%.*]] = sext i8 [[I2:%.*]] to i16
+; CHECK-NEXT:    [[SUB:%.*]] = add nsw i16 [[I1_EXT]], [[I2_EXT]]
+; CHECK-NEXT:    [[SHIFT:%.*]] = lshr i16 [[SUB]], 1
+; CHECK-NEXT:    [[T:%.*]] = trunc i16 [[SHIFT]] to i8
 ; CHECK-NEXT:    ret i8 [[T]]
 ;
   %i1.ext = sext i8 %i1 to i32
@@ -338,8 +338,8 @@
 ; CHECK-NEXT:    [[I1_EXT:%.*]] = sext i8 [[I1:%.*]] to i16
 ; CHECK-NEXT:    [[I2_EXT:%.*]] = sext i8 [[I2:%.*]] to i16
 ; CHECK-NEXT:    [[SUB:%.*]] = add nsw i16 [[I1_EXT]], [[I2_EXT]]
-; CHECK-NEXT:    [[SHIFT:%.*]] = lshr i16 [[SUB]], 1
-; CHECK-NEXT:    [[T:%.*]] = trunc i16 [[SHIFT]] to i8
+; CHECK-NEXT:    [[TMP1:%.*]] = lshr i16 [[SUB]], 1
+; CHECK-NEXT:    [[T:%.*]] = trunc i16 [[TMP1]] to i8
 ; CHECK-NEXT:    ret i8 [[T]]
 ;
   %i1.ext = sext i8 %i1 to i16