[clang] f1650cf - Revert "[clang] Convert second arg of __builtin_assume_aligned to ConstantExpr (#161314)" (#161719)

[via cfe-commits]

Author: Devon Loehr
Date: 2025-10-02T15:11:07-04:00
New Revision: f1650cf91b01470ce44f47797663d59f00828493

URL: https://github.com/llvm/llvm-project/commit/f1650cf91b01470ce44f47797663d59f00828493
DIFF: https://github.com/llvm/llvm-project/commit/f1650cf91b01470ce44f47797663d59f00828493.diff

LOG: Revert "[clang] Convert second arg of __builtin_assume_aligned to ConstantExpr (#161314)" (#161719)

This reverts commit 8f77621574176387f906b8ceef9e1abb90bf22f6 (#161314).

Reason: Causing crashes when building https://github.com/google/highway.
See the original PR for details.

Added: 
    

Modified: 
    clang/docs/ReleaseNotes.rst
    clang/lib/Sema/SemaChecking.cpp
    clang/test/SemaCXX/builtin-assume-aligned.cpp

Removed: 
    


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diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 74b0647f38795..145a83af514ed 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -246,8 +246,6 @@ Non-comprehensive list of changes in this release
 
 - ``__builtin_assume_dereferenceable`` now accepts non-constant size operands.
 
-- Fixed a crash when the second argument to ``__builtin_assume_aligned`` was not constant (#GH161314)
-
 New Compiler Flags
 ------------------
 - New option ``-fno-sanitize-debug-trap-reasons`` added to disable emitting trap reasons into the debug info when compiling with trapping UBSan (e.g. ``-fsanitize-trap=undefined``).

diff  --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 3cc61b167ba98..7ce3513fe0969 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -5954,9 +5954,6 @@ bool Sema::BuiltinAssumeAligned(CallExpr *TheCall) {
     if (Result > Sema::MaximumAlignment)
       Diag(TheCall->getBeginLoc(), diag::warn_assume_aligned_too_great)
           << SecondArg->getSourceRange() << Sema::MaximumAlignment;
-
-    TheCall->setArg(1,
-                    ConstantExpr::Create(Context, SecondArg, APValue(Result)));
   }
 
   if (NumArgs > 2) {

diff  --git a/clang/test/SemaCXX/builtin-assume-aligned.cpp b/clang/test/SemaCXX/builtin-assume-aligned.cpp
index afc11cc694705..48bd8414fc50a 100644
--- a/clang/test/SemaCXX/builtin-assume-aligned.cpp
+++ b/clang/test/SemaCXX/builtin-assume-aligned.cpp
@@ -47,9 +47,3 @@ constexpr void *s1 = __builtin_assume_aligned(x, 32);
 constexpr void *s2 = __builtin_assume_aligned(x, 32, 5);
 constexpr void *s3 = __builtin_assume_aligned(x, 32, -1);
 
-
-constexpr int add(int a, int b) {
-  return a+b;
-}
-constexpr void *c1 = __builtin_assume_aligned(p, add(1,1));
-constexpr void *c2 = __builtin_assume_aligned(p, add(2,1)); // expected-error {{not a power of 2}}