[llvm-branch-commits] [clang] release/21.x: [clang] Make sure EvalInfo pointer isn't null (#155563) (PR #155594)

[via llvm-branch-commits]

https://github.com/llvmbot created https://github.com/llvm/llvm-project/pull/155594

Backport 60cdc3ddeacd1310e8a014b076572c27e4886015

Requested by: @tbaederr

>From fb320a2e0f206f16b0957b8a4addebe94d704896 Mon Sep 17 00:00:00 2001
From: Timm Baeder <tbaeder at redhat.com>
Date: Wed, 27 Aug 2025 12:55:56 +0200
Subject: [PATCH] [clang] Make sure EvalInfo pointer isn't null (#155563)

It can be null, when called via CheckICE().
Accidentally introduced via #119366

Fixes #155507

(cherry picked from commit 60cdc3ddeacd1310e8a014b076572c27e4886015)
---
 clang/lib/AST/ExprConstant.cpp | 10 ++++++----
 clang/test/Sema/constexpr.c    |  7 +++++++
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 170da16a0cdf8..bfecae972940b 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -7909,8 +7909,9 @@ static bool checkBitCastConstexprEligibilityType(SourceLocation Loc,
       // so its layout is unspecified. For now, we'll simply treat these cases
       // as unsupported (this should only be possible with OpenCL bool vectors
       // whose element count isn't a multiple of the byte size).
-      Info->FFDiag(Loc, diag::note_constexpr_bit_cast_invalid_vector)
-          << QualType(VTy, 0) << EltSize << NElts << Ctx.getCharWidth();
+      if (Info)
+        Info->FFDiag(Loc, diag::note_constexpr_bit_cast_invalid_vector)
+            << QualType(VTy, 0) << EltSize << NElts << Ctx.getCharWidth();
       return false;
     }
 
@@ -7919,8 +7920,9 @@ static bool checkBitCastConstexprEligibilityType(SourceLocation Loc,
       // The layout for x86_fp80 vectors seems to be handled very inconsistently
       // by both clang and LLVM, so for now we won't allow bit_casts involving
       // it in a constexpr context.
-      Info->FFDiag(Loc, diag::note_constexpr_bit_cast_unsupported_type)
-          << EltTy;
+      if (Info)
+        Info->FFDiag(Loc, diag::note_constexpr_bit_cast_unsupported_type)
+            << EltTy;
       return false;
     }
   }
diff --git a/clang/test/Sema/constexpr.c b/clang/test/Sema/constexpr.c
index 3dcb0b3a7d95f..0987d175c91a8 100644
--- a/clang/test/Sema/constexpr.c
+++ b/clang/test/Sema/constexpr.c
@@ -391,3 +391,10 @@ void ghissue109095() {
   _Static_assert(i == c[0]); // expected-error {{static assertion expression is not an integral constant expression}}\
                              // expected-note {{initializer of 'i' is not a constant expression}}
 }
+
+typedef bool __vbool2  __attribute__((ext_vector_type(2)));
+typedef short v2int16_t __attribute__((ext_vector_type(2)));
+
+bool issue155507(v2int16_t a, v2int16_t b) {
+    return __builtin_bit_cast(unsigned char, __builtin_convertvector(a == b, __vbool2)) == 0b11;
+}