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... after a binary operation. The Result of the operation is in the common semantics of RHS and LHS, so we need to convert that to the semantics of the BinaryOperator expression.

... after a binary operation. The Result of the operation is in the
common semantics of RHS and LHS, so we need to convert that to the
semantics of the BinaryOperator expression.
@llvmbot llvmbot added clang Clang issues not falling into any other category clang:frontend Language frontend issues, e.g. anything involving "Sema" labels Sep 29, 2024
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llvmbot commented Sep 29, 2024

@llvm/pr-subscribers-clang

Author: Timm Baeder (tbaederr)

Changes

... after a binary operation. The Result of the operation is in the common semantics of RHS and LHS, so we need to convert that to the semantics of the BinaryOperator expression.


Full diff: https://github.com/llvm/llvm-project/pull/110411.diff

3 Files Affected:

  • (modified) clang/lib/AST/ByteCode/Compiler.cpp (+21-5)
  • (modified) clang/lib/AST/ByteCode/Interp.h (+2-1)
  • (modified) clang/test/AST/ByteCode/fixed-point.cpp (+2-4)
diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp
index 3a3ee3b577c29c..44195a3dc33de4 100644
--- a/clang/lib/AST/ByteCode/Compiler.cpp
+++ b/clang/lib/AST/ByteCode/Compiler.cpp
@@ -1502,25 +1502,41 @@ bool Compiler<Emitter>::VisitFixedPointBinOp(const BinaryOperator *E) {
   assert(LHS->getType()->isFixedPointType() ||
          RHS->getType()->isFixedPointType());
 
+  auto LHSSema = Ctx.getASTContext().getFixedPointSemantics(LHS->getType());
+  auto RHSSema = Ctx.getASTContext().getFixedPointSemantics(RHS->getType());
+
   if (!this->visit(LHS))
     return false;
   if (!LHS->getType()->isFixedPointType()) {
-    auto Sem = Ctx.getASTContext().getFixedPointSemantics(LHS->getType());
     uint32_t I;
-    std::memcpy(&I, &Sem, sizeof(Sem));
+    std::memcpy(&I, &LHSSema, sizeof(llvm::FixedPointSemantics));
     if (!this->emitCastIntegralFixedPoint(classifyPrim(LHS->getType()), I, E))
       return false;
   }
+
   if (!this->visit(RHS))
     return false;
   if (!RHS->getType()->isFixedPointType()) {
-    auto Sem = Ctx.getASTContext().getFixedPointSemantics(RHS->getType());
     uint32_t I;
-    std::memcpy(&I, &Sem, sizeof(Sem));
+    std::memcpy(&I, &RHSSema, sizeof(llvm::FixedPointSemantics));
     if (!this->emitCastIntegralFixedPoint(classifyPrim(RHS->getType()), I, E))
       return false;
   }
 
+  // Convert the result to the target semantics.
+  auto ConvertResult = [&](bool R) -> bool {
+    if (!R)
+      return false;
+    auto ResultSema = Ctx.getASTContext().getFixedPointSemantics(E->getType());
+    auto CommonSema = LHSSema.getCommonSemantics(RHSSema);
+    if (ResultSema != CommonSema) {
+      uint32_t I;
+      std::memcpy(&I, &ResultSema, sizeof(ResultSema));
+      return this->emitCastFixedPoint(I, E);
+    }
+    return true;
+  };
+
   switch (E->getOpcode()) {
   case BO_EQ:
     return this->emitEQFixedPoint(E);
@@ -1537,7 +1553,7 @@ bool Compiler<Emitter>::VisitFixedPointBinOp(const BinaryOperator *E) {
     return this->emitGEFixedPoint(E);
 #endif
   case BO_Add:
-    return this->emitAddFixedPoint(E);
+    return ConvertResult(this->emitAddFixedPoint(E));
 
   default:
     return this->emitInvalid(E);
diff --git a/clang/lib/AST/ByteCode/Interp.h b/clang/lib/AST/ByteCode/Interp.h
index fd09deb87d4c51..89635f9c61e932 100644
--- a/clang/lib/AST/ByteCode/Interp.h
+++ b/clang/lib/AST/ByteCode/Interp.h
@@ -2177,7 +2177,8 @@ inline bool CastFixedPoint(InterpState &S, CodePtr OpPC, uint32_t FPS) {
           E->getExprLoc(), diag::warn_fixedpoint_constant_overflow)
           << Result.toDiagnosticString(S.getASTContext()) << E->getType();
     }
-    S.CCEDiag(E, diag::note_constexpr_overflow) << Result << E->getType();
+    S.CCEDiag(E, diag::note_constexpr_overflow)
+        << Result.toDiagnosticString(S.getASTContext()) << E->getType();
     if (!S.noteUndefinedBehavior())
       return false;
   }
diff --git a/clang/test/AST/ByteCode/fixed-point.cpp b/clang/test/AST/ByteCode/fixed-point.cpp
index dd360382e7ca21..d515b7fe1594a9 100644
--- a/clang/test/AST/ByteCode/fixed-point.cpp
+++ b/clang/test/AST/ByteCode/fixed-point.cpp
@@ -42,10 +42,8 @@ namespace BinOps {
   static_assert(1 + A == 14.0k);
   static_assert((A + A) == 26);
 
-  /// FIXME: Conversion between fixed point semantics.
-  static_assert(A + 100000 == 14.0k); // expected-error {{static assertion failed}} \
-                                      // ref-error {{is not an integral constant expression}} \
-                                      // ref-note {{is outside the range of representable values}}
+  static_assert(A + 100000 == 14.0k); // both-error {{is not an integral constant expression}} \
+                                      // both-note {{is outside the range of representable values}}
 }
 
 namespace FixedPointCasts {

@tbaederr tbaederr merged commit 1714b11 into llvm:main Sep 29, 2024
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llvm-ci commented Sep 29, 2024

LLVM Buildbot has detected a new failure on builder openmp-s390x-linux running on systemz-1 while building clang at step 6 "test-openmp".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/88/builds/2922

Here is the relevant piece of the build log for the reference
Step 6 (test-openmp) failure: test (failure)
******************** TEST 'libomp :: tasking/issue-94260-2.c' FAILED ********************
Exit Code: -11

Command Output (stdout):
--
# RUN: at line 1
/home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/./bin/clang -fopenmp   -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test -L /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/src  -fno-omit-frame-pointer -mbackchain -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/ompt /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/tasking/issue-94260-2.c -o /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/tasking/Output/issue-94260-2.c.tmp -lm -latomic && /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/tasking/Output/issue-94260-2.c.tmp
# executed command: /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/./bin/clang -fopenmp -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test -L /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -fno-omit-frame-pointer -mbackchain -I /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/ompt /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.src/openmp/runtime/test/tasking/issue-94260-2.c -o /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/tasking/Output/issue-94260-2.c.tmp -lm -latomic
# executed command: /home/uweigand/sandbox/buildbot/openmp-s390x-linux/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/tasking/Output/issue-94260-2.c.tmp
# note: command had no output on stdout or stderr
# error: command failed with exit status: -11

--

********************


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