[Clang] Fix a crash introduced in PR#88666

[shiltian]

The unroll value can be a template variable such that we need to check it before
we verify if it is constant value.

[llvmbot]

@llvm/pr-subscribers-clang

Author: Shilei Tian (shiltian)

Changes

The unroll value can be a template variable such that we need to check it before
we verify if it is constant value.

---

Full diff: https://github.com/llvm/llvm-project/pull/89567.diff

2 Files Affected:

• (modified) clang/lib/Sema/SemaStmtAttr.cpp (+1-1)
• (added) clang/test/Sema/unroll-template-value-crash.cpp (+7)

diff --git a/clang/lib/Sema/SemaStmtAttr.cpp b/clang/lib/Sema/SemaStmtAttr.cpp
index 7cd494b42250d4..9d44c22c8ddcc3 100644
--- a/clang/lib/Sema/SemaStmtAttr.cpp
+++ b/clang/lib/Sema/SemaStmtAttr.cpp
@@ -109,7 +109,7 @@ static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const ParsedAttr &A,
     SetHints(LoopHintAttr::Unroll, LoopHintAttr::Disable);
   } else if (PragmaName == "unroll") {
     // #pragma unroll N
-    if (ValueExpr) {
+    if (ValueExpr && !ValueExpr->isValueDependent()) {
       llvm::APSInt ValueAPS;
       ExprResult R = S.VerifyIntegerConstantExpression(ValueExpr, &ValueAPS);
       assert(!R.isInvalid() && "unroll count value must be a valid value, it's "
diff --git a/clang/test/Sema/unroll-template-value-crash.cpp b/clang/test/Sema/unroll-template-value-crash.cpp
new file mode 100644
index 00000000000000..bb200fc3667c8f
--- /dev/null
+++ b/clang/test/Sema/unroll-template-value-crash.cpp
@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 -x c++ -emit-llvm -S -verify %s
+// expected-no-diagnostics
+
+template <int Unroll> void foo() {
+  #pragma unroll Unroll
+  for (int i = 0; i < Unroll; ++i);
+}

[yronglin]

Thanks for your fix, LGTM!