[clang] Report erroneous floating point results in _Complex math (#90588)

Use handleFloatFloatBinOp to properly diagnose NaN results and divisions
by zero.

Fixes #84871

2 files changed, 55 insertions, 33 deletions

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index f1aa19e..86fb396 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -15209,11 +15209,21 @@ bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
       APFloat &ResI = Result.getComplexFloatImag();
       if (LHSReal) {
         assert(!RHSReal && "Cannot have two real operands for a complex op!");
-        ResR = A * C;
-        ResI = A * D;
+        ResR = A;
+        ResI = A;
+        // ResR = A * C;
+        // ResI = A * D;
+        if (!handleFloatFloatBinOp(Info, E, ResR, BO_Mul, C) ||
+            !handleFloatFloatBinOp(Info, E, ResI, BO_Mul, D))
+          return false;
       } else if (RHSReal) {
-        ResR = C * A;
-        ResI = C * B;
+        // ResR = C * A;
+        // ResI = C * B;
+        ResR = C;
+        ResI = C;
+        if (!handleFloatFloatBinOp(Info, E, ResR, BO_Mul, A) ||
+            !handleFloatFloatBinOp(Info, E, ResI, BO_Mul, B))
+          return false;
       } else {
         // In the fully general case, we need to handle NaNs and infinities
         // robustly.
@@ -15289,8 +15299,13 @@ bool ComplexExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
       APFloat &ResR = Result.getComplexFloatReal();
       APFloat &ResI = Result.getComplexFloatImag();
       if (RHSReal) {
-        ResR = A / C;
-        ResI = B / C;
+        ResR = A;
+        ResI = B;
+        // ResR = A / C;
+        // ResI = B / C;
+        if (!handleFloatFloatBinOp(Info, E, ResR, BO_Div, C) ||
+            !handleFloatFloatBinOp(Info, E, ResI, BO_Div, C))
+          return false;
       } else {
         if (LHSReal) {
           // No real optimizations we can do here, stub out with zero.
diff --git a/clang/test/SemaCXX/complex-folding.cpp b/clang/test/SemaCXX/complex-folding.cpp
index 054f159..7bfd36f 100644
--- a/clang/test/SemaCXX/complex-folding.cpp
+++ b/clang/test/SemaCXX/complex-folding.cpp
@@ -59,41 +59,48 @@ static_assert((1.25 / (0.25 - 0.75j)) == (0.5 + 1.5j));
 
 // Test that infinities are preserved, don't turn into NaNs, and do form zeros
 // when the divisor.
+constexpr _Complex float InfC = {1.0, __builtin_inf()};
+constexpr _Complex float InfInf = __builtin_inf() + InfC;
+static_assert(__real__(InfInf) == __builtin_inf());
+static_assert(__imag__(InfInf) == __builtin_inf());
+static_assert(__builtin_isnan(__real__(InfInf * InfInf)));
+static_assert(__builtin_isinf_sign(__imag__(InfInf * InfInf)) == 1);
+
 static_assert(__builtin_isinf_sign(__real__((__builtin_inf() + 1.0j) * 1.0)) == 1);
-static_assert(__builtin_isinf_sign(__imag__((1.0 + __builtin_inf() * 1.0j) * 1.0)) == 1);
+static_assert(__builtin_isinf_sign(__imag__((1.0 + InfC) * 1.0)) == 1);
 static_assert(__builtin_isinf_sign(__real__(1.0 * (__builtin_inf() + 1.0j))) == 1);
-static_assert(__builtin_isinf_sign(__imag__(1.0 * (1.0 + __builtin_inf() * 1.0j))) == 1);
-
+static_assert(__builtin_isinf_sign(__imag__(1.0 * (1.0 + InfC))) == 1);
 static_assert(__builtin_isinf_sign(__real__((__builtin_inf() + 1.0j) * (1.0 + 1.0j))) == 1);
 static_assert(__builtin_isinf_sign(__real__((1.0 + 1.0j) * (__builtin_inf() + 1.0j))) == 1);
 static_assert(__builtin_isinf_sign(__real__((__builtin_inf() + 1.0j) * (__builtin_inf() + 1.0j))) == 1);
-
-static_assert(__builtin_isinf_sign(__real__((1.0 + __builtin_inf() * 1.0j) * (1.0 + 1.0j))) == -1);
-static_assert(__builtin_isinf_sign(__imag__((1.0 + __builtin_inf() * 1.0j) * (1.0 + 1.0j))) == 1);
-static_assert(__builtin_isinf_sign(__real__((1.0 + 1.0j) * (1.0 + __builtin_inf() * 1.0j))) == -1);
-static_assert(__builtin_isinf_sign(__imag__((1.0 + 1.0j) * (1.0 + __builtin_inf() * 1.0j))) == 1);
-
-static_assert(__builtin_isinf_sign(__real__((1.0 + __builtin_inf() * 1.0j) * (1.0 + __builtin_inf() * 1.0j))) == -1);
-static_assert(__builtin_isinf_sign(__real__((__builtin_inf() + __builtin_inf() * 1.0j) * (__builtin_inf() + __builtin_inf() * 1.0j))) == -1);
-
+static_assert(__builtin_isinf_sign(__real__((1.0 + InfC) * (1.0 + 1.0j))) == -1);
+static_assert(__builtin_isinf_sign(__imag__((1.0 + InfC) * (1.0 + 1.0j))) == 1);
+static_assert(__builtin_isinf_sign(__real__((1.0 + 1.0j) * (1.0 + InfC))) == -1);
+static_assert(__builtin_isinf_sign(__imag__((1.0 + 1.0j) * (1.0 + InfC))) == 1);
+static_assert(__builtin_isinf_sign(__real__((1.0 + InfC) * (1.0 + InfC))) == -1);
+static_assert(__builtin_isinf_sign(__real__(InfInf * InfInf)) == 0);
 static_assert(__builtin_isinf_sign(__real__((__builtin_inf() + 1.0j) / (1.0 + 1.0j))) == 1);
-static_assert(__builtin_isinf_sign(__imag__(1.0 + (__builtin_inf() * 1.0j) / (1.0 + 1.0j))) == 1);
-static_assert(__builtin_isinf_sign(__imag__((__builtin_inf() + __builtin_inf() * 1.0j) / (1.0 + 1.0j))) == 1);
+static_assert(__builtin_isinf_sign(__imag__(1.0 + (InfC) / (1.0 + 1.0j))) == 1);
+static_assert(__builtin_isinf_sign(__imag__((InfInf) / (1.0 + 1.0j))) == 0);
 static_assert(__builtin_isinf_sign(__real__((__builtin_inf() + 1.0j) / 1.0)) == 1);
-static_assert(__builtin_isinf_sign(__imag__(1.0 + (__builtin_inf() * 1.0j) / 1.0)) == 1);
-static_assert(__builtin_isinf_sign(__imag__((__builtin_inf() + __builtin_inf() * 1.0j) / 1.0)) == 1);
-
+static_assert(__builtin_isinf_sign(__imag__(1.0 + (InfC) / 1.0)) == 1);
+static_assert(__builtin_isinf_sign(__imag__((InfInf) / 1.0)) == 1);
 static_assert(((1.0 + 1.0j) / (__builtin_inf() + 1.0j)) == (0.0 + 0.0j));
-static_assert(((1.0 + 1.0j) / (1.0 + __builtin_inf() * 1.0j)) == (0.0 + 0.0j));
-static_assert(((1.0 + 1.0j) / (__builtin_inf() + __builtin_inf() * 1.0j)) == (0.0 + 0.0j));
+static_assert(((1.0 + 1.0j) / (1.0 + InfC)) == (0.0 + 0.0j));
+static_assert(((1.0 + 1.0j) / (InfInf)) == (0.0 + 0.0j));
 static_assert(((1.0 + 1.0j) / __builtin_inf()) == (0.0 + 0.0j));
-
+static_assert(1.0j / 0.0 == 1); // expected-error {{static assertion}} \
+                                // expected-note {{division by zero}}
 static_assert(__builtin_isinf_sign(__real__((1.0 + 1.0j) / (0.0 + 0.0j))) == 1);
-static_assert(__builtin_isinf_sign(__real__((1.0 + 1.0j) / 0.0)) == 1);
-
+static_assert(__builtin_isinf_sign(__real__((1.0 + 1.0j) / 0.0)) == 1); // expected-error {{static assertion}} \
+                                                                        // expected-note {{division by zero}}
 static_assert(__builtin_isinf_sign(__real__((__builtin_inf() + 1.0j) / (0.0 + 0.0j))) == 1);
-static_assert(__builtin_isinf_sign(__imag__((1.0 + __builtin_inf() * 1.0j) / (0.0 + 0.0j))) == 1);
-static_assert(__builtin_isinf_sign(__imag__((__builtin_inf() + __builtin_inf() * 1.0j) / (0.0 + 0.0j))) == 1);
-static_assert(__builtin_isinf_sign(__real__((__builtin_inf() + 1.0j) / 0.0)) == 1);
-static_assert(__builtin_isinf_sign(__imag__((1.0 + __builtin_inf() * 1.0j) / 0.0)) == 1);
-static_assert(__builtin_isinf_sign(__imag__((__builtin_inf() + __builtin_inf() * 1.0j) / 0.0)) == 1);
+static_assert(__builtin_isinf_sign(__imag__((1.0 + InfC) / (0.0 + 0.0j))) == 1);
+static_assert(__builtin_isinf_sign(__imag__((InfInf) / (0.0 + 0.0j))) == 1);
+static_assert(__builtin_isinf_sign(__real__((__builtin_inf() + 1.0j) / 0.0)) == 1); // expected-error {{static assertion}} \
+                                                                                    // expected-note {{division by zero}}
+static_assert(__builtin_isinf_sign(__imag__((1.0 + InfC) / 0.0)) == 1); // expected-error {{static assertion}} \
+                                                                        // expected-note {{division by zero}}
+static_assert(__builtin_isinf_sign(__imag__((InfInf) / 0.0)) == 1); // expected-error {{static assertion}} \
+                                                                    // expected-note {{division by zero}}
+