Fix mem2reg bug

Author: wsmoses

lib/polygeist/Passes/Mem2Reg.cpp

@@ -511,7 +511,7 @@ class ValueOrPlaceholder {
                llvm::zip(ifOp.getResults(), getThenYield(ifOp).getOperands(),
                          getElseYield(ifOp).getOperands()))) {
         if (std::get<1>(tup) == thenVal && std::get<2>(tup) == elseVal) {
-          return thenVal;
+          return std::get<0>(tup);
         }
       }
     }
@@ -571,7 +571,7 @@ static inline llvm::raw_ostream &operator<<(llvm::raw_ostream &os,
     ;
   }
   if (PH.ifOp)
-    return os << "ifOp:" << PH.ifOp;
+    return os << "ifOp:" << *PH.ifOp;
   if (PH.exOp)
     return os << "exOp:" << PH.exOp;
   return os;

test/polygeist-opt/mem2regIf2.mlir

@@ -37,3 +37,58 @@ module {
 // CHECK-NEXT:     }
 // CHECK-NEXT:     return %2 : f32
 // CHECK-NEXT:   }
+
+// ----
+
+module {
+  func private @gen() -> (!llvm.ptr<i8>)
+
+func @_Z3runiPPc(%arg2: i1) -> !llvm.ptr<i8> {
+  %c1_i64 = arith.constant 1 : i64
+  %0 = llvm.alloca %c1_i64 x !llvm.ptr<i8> : (i64) -> !llvm.ptr<ptr<i8>>
+  %2 = llvm.mlir.null : !llvm.ptr<i8>
+  scf.if %arg2 {
+    %5 = llvm.load %0 : !llvm.ptr<ptr<i8>>
+    %6 = llvm.icmp "eq" %5, %2 : !llvm.ptr<i8>
+    %7 = scf.if %6 -> (!llvm.ptr<i8>) {
+      %8 = scf.if %arg2 -> (!llvm.ptr<i8>) {
+        %9 = call @gen() : () -> !llvm.ptr<i8>
+        llvm.store %9, %0 : !llvm.ptr<ptr<i8>>
+        scf.yield %9 : !llvm.ptr<i8>
+      } else {
+        scf.yield %5 : !llvm.ptr<i8>
+      }
+      scf.yield %8 : !llvm.ptr<i8>
+    } else {
+      scf.yield %5 : !llvm.ptr<i8>
+    }
+  }
+  %4 = llvm.load %0 : !llvm.ptr<ptr<i8>>
+  return %4 : !llvm.ptr<i8>
+}
+
+}
+
+// CHECK:     func @_Z3runiPPc(%arg0: i1) -> !llvm.ptr<i8> {
+// CHECK-NEXT:       %c1_i64 = arith.constant 1 : i64
+// CHECK-NEXT:       %0 = llvm.alloca %c1_i64 x !llvm.ptr<i8> : (i64) -> !llvm.ptr<ptr<i8>>
+// CHECK-NEXT:       %1 = llvm.mlir.null : !llvm.ptr<i8>
+// CHECK-NEXT:       scf.if %arg0 {
+// CHECK-NEXT:         %3 = llvm.load %0 : !llvm.ptr<ptr<i8>>
+// CHECK-NEXT:         %4 = llvm.icmp "eq" %3, %1 : !llvm.ptr<i8>
+// CHECK-NEXT:         %5 = scf.if %4 -> (!llvm.ptr<i8>) {
+// CHECK-NEXT:           %6 = scf.if %arg0 -> (!llvm.ptr<i8>) {
+// CHECK-NEXT:             %7 = call @gen() : () -> !llvm.ptr<i8>
+// CHECK-NEXT:             llvm.store %7, %0 : !llvm.ptr<ptr<i8>>
+// CHECK-NEXT:             scf.yield %7 : !llvm.ptr<i8>
+// CHECK-NEXT:           } else {
+// CHECK-NEXT:             scf.yield %3 : !llvm.ptr<i8>
+// CHECK-NEXT:           }
+// CHECK-NEXT:           scf.yield %6 : !llvm.ptr<i8>
+// CHECK-NEXT:         } else {
+// CHECK-NEXT:           scf.yield %3 : !llvm.ptr<i8>
+// CHECK-NEXT:         }
+// CHECK-NEXT:       }
+// CHECK-NEXT:       %2 = llvm.load %0 : !llvm.ptr<ptr<i8>>
+// CHECK-NEXT:       return %2 : !llvm.ptr<i8>
+