From 8f25523cd4f0330e0f45a997ec940a05ca8468b6 Mon Sep 17 00:00:00 2001
From: Kirill Yansitov <36601354+YazZz1k@users.noreply.github.com>
Date: Thu, 8 Feb 2024 23:08:10 +0300
Subject: [PATCH] [CIR][CIRGen][Bugfix] Emit valid type for evaluated const
 (#456)

This PR fixes the issue connected with folding a simple boolean
expresion pattern (f.e. `0 && RHS = 0`).
The problem is that the scalar expression emitter always creates a
`cir.bool` attribute as a result of expression. But in some cases the
result expression should be a `cir.int` attr.
---
 clang/lib/CIR/CodeGen/CIRGenBuilder.h      | 11 +----------
 clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp | 10 +++++++---
 clang/test/CIR/CodeGen/evaluate-expr.c     | 20 ++++++++++++++++++++
 3 files changed, 28 insertions(+), 13 deletions(-)
 create mode 100644 clang/test/CIR/CodeGen/evaluate-expr.c

diff --git a/clang/lib/CIR/CodeGen/CIRGenBuilder.h b/clang/lib/CIR/CodeGen/CIRGenBuilder.h
index 35d6bcf5b5d1..19b01c5405b2 100644
--- a/clang/lib/CIR/CodeGen/CIRGenBuilder.h
+++ b/clang/lib/CIR/CodeGen/CIRGenBuilder.h
@@ -552,16 +552,7 @@ class CIRGenBuilderTy : public CIRBaseBuilderTy {
 
   // Creates constant null value for integral type ty.
   mlir::cir::ConstantOp getNullValue(mlir::Type ty, mlir::Location loc) {
-    if (ty.isa<mlir::cir::PointerType>())
-      return getNullPtr(ty, loc);
-
-    mlir::TypedAttr attr;
-    if (ty.isa<mlir::cir::IntType>())
-      attr = mlir::cir::IntAttr::get(ty, 0);
-    else
-      llvm_unreachable("NYI");
-
-    return create<mlir::cir::ConstantOp>(loc, ty, attr);
+    return create<mlir::cir::ConstantOp>(loc, ty, getZeroInitAttr(ty));
   }
 
   mlir::cir::ConstantOp getZero(mlir::Location loc, mlir::Type ty) {
diff --git a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
index 96c5da4f2c82..de18fa610970 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprScalar.cpp
@@ -2147,7 +2147,7 @@ mlir::Value ScalarExprEmitter::VisitBinLAnd(const clang::BinaryOperator *E) {
     }
     // 0 && RHS: If it is safe, just elide the RHS, and return 0/false.
     if (!CGF.ContainsLabel(E->getRHS()))
-      return Builder.getBool(false, Loc);
+      return Builder.getNullValue(ResTy, Loc);
   }
 
   CIRGenFunction::ConditionalEvaluation eval(CGF);
@@ -2220,8 +2220,12 @@ mlir::Value ScalarExprEmitter::VisitBinLOr(const clang::BinaryOperator *E) {
       return Builder.createZExtOrBitCast(RHSCond.getLoc(), RHSCond, ResTy);
     }
     // 1 || RHS: If it is safe, just elide the RHS, and return 1/true.
-    if (!CGF.ContainsLabel(E->getRHS()))
-      return Builder.getBool(true, Loc);
+    if (!CGF.ContainsLabel(E->getRHS())) {
+      if (auto intTy = ResTy.dyn_cast<mlir::cir::IntType>())
+        return Builder.getConstInt(Loc, intTy, 1);
+      else
+        return Builder.getBool(true, Loc);
+    }
   }
 
   CIRGenFunction::ConditionalEvaluation eval(CGF);
diff --git a/clang/test/CIR/CodeGen/evaluate-expr.c b/clang/test/CIR/CodeGen/evaluate-expr.c
new file mode 100644
index 000000000000..d468bf1340db
--- /dev/null
+++ b/clang/test/CIR/CodeGen/evaluate-expr.c
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir-enable -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s
+
+static const int g = 1;
+void foo() {
+  if ((g != 1) && (g != 1))
+    return;
+  if ((g == 1) || (g == 1))
+    return;
+}
+// CHECK:  cir.func no_proto @foo()
+// CHECK:    cir.scope {
+// CHECK:      [[ZERO:%.*]] = cir.const(#cir.int<0> : !s32i) : !s32i
+// CHECK:      [[FALSE:%.*]] = cir.cast(int_to_bool, [[ZERO:%.*]] : !s32i), !cir.bool
+// CHECK:      cir.if [[FALSE]] {
+// CHECK:        cir.return
+// CHECK:      }
+// CHECK:    }
+// CHECK:    cir.return
+