diff --git a/llvm/test/TableGen/address-space-patfrags.td b/llvm/test/TableGen/address-space-patfrags.td
--- a/llvm/test/TableGen/address-space-patfrags.td
+++ b/llvm/test/TableGen/address-space-patfrags.td
@@ -44,6 +44,11 @@
   let InOperandList = (ins GPR32:$src0, GPR32:$src1);
 }
 
+def inst_d : Instruction {
+  let OutOperandList = (outs);
+  let InOperandList = (ins GPR32:$src0, GPR32:$src1);
+}
+
 // SDAG: case 2: {
 // SDAG-NEXT: // Predicate_pat_frag_b
 // SDAG-NEXT: SDNode *N = Node;
@@ -119,6 +124,16 @@
 // GISEL: GIM_Try, /*On fail goto*//*Label 3*/ {{[0-9]+}}, // Rule ID 3 //
 // GISEL-NEXT: GIM_CheckNumOperands, /*MI*/0, /*Expected*/2,
 // GISEL-NEXT: GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_STORE,
+// GISEL-NEXT: GIM_CheckMemorySizeEqualToLLT, /*MI*/0, /*MMO*/0, /*OpIdx*/0,
+def : Pat <
+  (store GPR32:$src0, GPR32:$src1),
+  (inst_d GPR32:$src0, GPR32:$src1)
+>;
+
+// Test truncstore with specific MemoryVT
+// GISEL: GIM_Try, /*On fail goto*//*Label 4*/ {{[0-9]+}}, // Rule ID 4 //
+// GISEL-NEXT: GIM_CheckNumOperands, /*MI*/0, /*Expected*/2,
+// GISEL-NEXT: GIM_CheckOpcode, /*MI*/0, TargetOpcode::G_STORE,
 // GISEL-NEXT: GIM_CheckMemorySizeLessThanLLT, /*MI*/0, /*MMO*/0, /*OpIdx*/0,
 // GISEL-NEXT: GIM_CheckMemoryAddressSpace, /*MI*/0, /*MMO*/0, /*NumAddrSpace*/2, /*AddrSpace*/123, /*AddrSpace*/455,
 // GISEL-NEXT: GIM_CheckMemorySizeEqualTo, /*MI*/0, /*MMO*/0, /*Size*/2,
diff --git a/llvm/utils/TableGen/GlobalISelEmitter.cpp b/llvm/utils/TableGen/GlobalISelEmitter.cpp
--- a/llvm/utils/TableGen/GlobalISelEmitter.cpp
+++ b/llvm/utils/TableGen/GlobalISelEmitter.cpp
@@ -3347,11 +3347,19 @@
       continue;
     }
 
-    if (Predicate.isStore() && Predicate.isTruncStore()) {
-      // FIXME: If MemoryVT is set, we end up with 2 checks for the MMO size.
-      InsnMatcher.addPredicate<MemoryVsLLTSizePredicateMatcher>(
-        0, MemoryVsLLTSizePredicateMatcher::LessThan, 0);
-      continue;
+    if (Predicate.isStore()) {
+      if (Predicate.isTruncStore()) {
+        // FIXME: If MemoryVT is set, we end up with 2 checks for the MMO size.
+        InsnMatcher.addPredicate<MemoryVsLLTSizePredicateMatcher>(
+            0, MemoryVsLLTSizePredicateMatcher::LessThan, 0);
+        continue;
+      }
+      if (Predicate.isNonTruncStore()) {
+        // We need to check the sizes match here otherwise we could incorrectly
+        // match truncating stores with non-truncating ones.
+        InsnMatcher.addPredicate<MemoryVsLLTSizePredicateMatcher>(
+            0, MemoryVsLLTSizePredicateMatcher::EqualTo, 0);
+      }
     }
 
     // No check required. We already did it by swapping the opcode.