Index: llvm/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/lib/Analysis/ValueTracking.cpp
+++ llvm/lib/Analysis/ValueTracking.cpp
@@ -158,6 +158,11 @@
   if (CxtI && CxtI->getParent())
     return CxtI;
 
+  // For an argument, we can use the start of the function.
+  if (auto *A = dyn_cast<Argument>(V))
+    if (A->getParent() && !A->getParent()->empty())
+      return CxtI = &*(A->getParent()->getEntryBlock().begin());
+
   return nullptr;
 }
 
@@ -176,6 +181,15 @@
   if (CxtI && CxtI->getParent())
     return CxtI;
 
+  // For an argument, we can use the start of the function.
+  if (auto *A = dyn_cast<Argument>(V1))
+    if (A->getParent() && !A->getParent()->empty())
+      return CxtI = &*(A->getParent()->getEntryBlock().begin());
+
+  if (auto *A = dyn_cast<Argument>(V2))
+    if (A->getParent() && !A->getParent()->empty())
+      return CxtI = &*(A->getParent()->getEntryBlock().begin());
+
   return nullptr;
 }
 
Index: llvm/test/Analysis/ScalarEvolution/ranges.ll
===================================================================
--- llvm/test/Analysis/ScalarEvolution/ranges.ll
+++ llvm/test/Analysis/ScalarEvolution/ranges.ll
@@ -43,7 +43,7 @@
 ; CHECK-LABEL: 'shl'
 ; CHECK-NEXT:  Classifying expressions for: @shl
 ; CHECK-NEXT:    %res = shl i32 %a, 2
-; CHECK-NEXT:    --> (4 * %a) U: [0,-3) S: [-2147483648,2147483645)
+; CHECK-NEXT:    --> (4 * %a)<nuw><nsw> U: [0,4093) S: [0,4093)
 ; CHECK-NEXT:  Determining loop execution counts for: @shl
 ;
   %res = shl i32 %a, 2
@@ -56,7 +56,7 @@
 ; CHECK-LABEL: 'lshr'
 ; CHECK-NEXT:  Classifying expressions for: @lshr
 ; CHECK-NEXT:    %res = lshr i32 %a, 31
-; CHECK-NEXT:    --> (%a /u -2147483648) U: [0,2) S: [0,2)
+; CHECK-NEXT:    --> (%a /u -2147483648) U: [0,1) S: [0,1)
 ; CHECK-NEXT:  Determining loop execution counts for: @lshr
 ;
   %res = lshr i32 %a, 31
@@ -70,7 +70,7 @@
 ; CHECK-LABEL: 'udiv'
 ; CHECK-NEXT:  Classifying expressions for: @udiv
 ; CHECK-NEXT:    %res = udiv i32 %a, -2147483648
-; CHECK-NEXT:    --> (%a /u -2147483648) U: [0,2) S: [0,2)
+; CHECK-NEXT:    --> (%a /u -2147483648) U: [0,1) S: [0,1)
 ; CHECK-NEXT:  Determining loop execution counts for: @udiv
 ;
   %res = udiv i32 %a, 2147483648
@@ -83,7 +83,7 @@
 ; CHECK-LABEL: 'sext'
 ; CHECK-NEXT:  Classifying expressions for: @sext
 ; CHECK-NEXT:    %res = sext i8 %a to i64
-; CHECK-NEXT:    --> (sext i8 %a to i64) U: [-128,128) S: [-128,128)
+; CHECK-NEXT:    --> (zext i8 %a to i64) U: [0,128) S: [0,128)
 ; CHECK-NEXT:  Determining loop execution counts for: @sext
 ;
   %res = sext i8 %a to i64
@@ -96,7 +96,7 @@
 ; CHECK-LABEL: 'zext'
 ; CHECK-NEXT:  Classifying expressions for: @zext
 ; CHECK-NEXT:    %res = zext i8 %a to i64
-; CHECK-NEXT:    --> (zext i8 %a to i64) U: [0,256) S: [0,256)
+; CHECK-NEXT:    --> (zext i8 %a to i64) U: [0,128) S: [0,128)
 ; CHECK-NEXT:  Determining loop execution counts for: @zext
 ;
   %res = zext i8 %a to i64