diff --git a/source/opt/fold.cpp b/source/opt/fold.cpp
index d6b583f..0604da2 100644
--- a/source/opt/fold.cpp
+++ b/source/opt/fold.cpp
@@ -115,8 +115,10 @@
 
     // Shifting
     case SpvOp::SpvOpShiftRightLogical:
-      if (b > 32) {
-        // This is undefined behaviour.  Choose 0 for consistency.
+      if (b >= 32) {
+        // This is undefined behaviour when |b| > 32.  Choose 0 for consistency.
+        // When |b| == 32, doing the shift in C++ in undefined, but the result
+        // will be 0, so just return that value.
         return 0;
       }
       return a >> b;
@@ -125,10 +127,21 @@
         // This is undefined behaviour.  Choose 0 for consistency.
         return 0;
       }
+      if (b == 32) {
+        // Doing the shift in C++ is undefined, but the result is defined in the
+        // spir-v spec.  Find that value another way.
+        if (static_cast<int32_t>(a) >= 0) {
+          return 0;
+        } else {
+          return static_cast<uint32_t>(-1);
+        }
+      }
       return (static_cast<int32_t>(a)) >> b;
     case SpvOp::SpvOpShiftLeftLogical:
-      if (b > 32) {
-        // This is undefined behaviour.  Choose 0 for consistency.
+      if (b >= 32) {
+        // This is undefined behaviour when |b| > 32.  Choose 0 for consistency.
+        // When |b| == 32, doing the shift in C++ in undefined, but the result
+        // will be 0, so just return that value.
         return 0;
       }
       return a << b;
@@ -307,7 +320,8 @@
       if (constants[1] != nullptr) {
         // When shifting by a value larger than the size of the result, the
         // result is undefined.  We are setting the undefined behaviour to a
-        // result of 0.
+        // result of 0.  If the shift amount is the same as the size of the
+        // result, then the result is defined, and it 0.
         uint32_t shift_amount = constants[1]->GetU32BitValue();
         if (shift_amount >= 32) {
           *result = 0;
diff --git a/test/opt/fold_test.cpp b/test/opt/fold_test.cpp
index 1a54421..88248ba 100644
--- a/test/opt/fold_test.cpp
+++ b/test/opt/fold_test.cpp
@@ -168,6 +168,7 @@
 %int_2 = OpConstant %int 2
 %int_3 = OpConstant %int 3
 %int_4 = OpConstant %int 4
+%int_n24 = OpConstant %int -24
 %int_min = OpConstant %int -2147483648
 %int_max = OpConstant %int 2147483647
 %long_0 = OpConstant %long 0
@@ -486,7 +487,7 @@
           "OpReturn\n" +
           "OpFunctionEnd",
       2, 0),
-  // Test case 21: fold signed n >> 42 (undefined, so set to zero).
+  // Test case 23: fold signed n >> 42 (undefined, so set to zero).
   InstructionFoldingCase<uint32_t>(
       Header() + "%main = OpFunction %void None %void_func\n" +
           "%main_lab = OpLabel\n" +
@@ -496,7 +497,7 @@
           "OpReturn\n" +
           "OpFunctionEnd",
       2, 0),
-  // Test case 22: fold n << 42 (undefined, so set to zero).
+  // Test case 24: fold n << 42 (undefined, so set to zero).
   InstructionFoldingCase<uint32_t>(
       Header() + "%main = OpFunction %void None %void_func\n" +
           "%main_lab = OpLabel\n" +
@@ -505,6 +506,38 @@
           "%2 = OpShiftLeftLogical %int %load %uint_42\n" +
           "OpReturn\n" +
           "OpFunctionEnd",
+      2, 0),
+  // Test case 25: fold -24 >> 32 (defined as -1)
+  InstructionFoldingCase<uint32_t>(
+      Header() + "%main = OpFunction %void None %void_func\n" +
+          "%main_lab = OpLabel\n" +
+          "%2 = OpShiftRightArithmetic %int %int_n24 %uint_32\n" +
+          "OpReturn\n" +
+          "OpFunctionEnd",
+      2, -1),
+  // Test case 26: fold 2 >> 32 (signed)
+  InstructionFoldingCase<uint32_t>(
+      Header() + "%main = OpFunction %void None %void_func\n" +
+          "%main_lab = OpLabel\n" +
+          "%2 = OpShiftRightArithmetic %int %int_2 %uint_32\n" +
+          "OpReturn\n" +
+          "OpFunctionEnd",
+      2, 0),
+  // Test case 27: fold 2 >> 32 (unsigned)
+  InstructionFoldingCase<uint32_t>(
+      Header() + "%main = OpFunction %void None %void_func\n" +
+          "%main_lab = OpLabel\n" +
+          "%2 = OpShiftRightLogical %int %int_2 %uint_32\n" +
+          "OpReturn\n" +
+          "OpFunctionEnd",
+      2, 0),
+  // Test case 28: fold 2 << 32
+  InstructionFoldingCase<uint32_t>(
+      Header() + "%main = OpFunction %void None %void_func\n" +
+          "%main_lab = OpLabel\n" +
+          "%2 = OpShiftLeftLogical %int %int_2 %uint_32\n" +
+          "OpReturn\n" +
+          "OpFunctionEnd",
       2, 0)
 ));
 // clang-format on