[clang][Interp] Implement IntegralAP::{div, rem}

[tbaederr]

No description provided.

[llvmbot]

@llvm/pr-subscribers-clang

Author: Timm Baeder (tbaederr)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/72614.diff

2 Files Affected:

• (modified) clang/lib/AST/Interp/IntegralAP.h (+8-4)
• (modified) clang/test/AST/Interp/intap.cpp (+18)

diff --git a/clang/lib/AST/Interp/IntegralAP.h b/clang/lib/AST/Interp/IntegralAP.h
index 9019f32e6cef2a3..17fc0695c98bb70 100644
--- a/clang/lib/AST/Interp/IntegralAP.h
+++ b/clang/lib/AST/Interp/IntegralAP.h
@@ -208,14 +208,18 @@ template <bool Signed> class IntegralAP final {
   }
 
   static bool rem(IntegralAP A, IntegralAP B, unsigned OpBits, IntegralAP *R) {
-    // FIXME: Implement.
-    assert(false);
+    if constexpr (Signed)
+      *R = IntegralAP(A.V.srem(B.V));
+    else
+      *R = IntegralAP(A.V.urem(B.V));
     return false;
   }
 
   static bool div(IntegralAP A, IntegralAP B, unsigned OpBits, IntegralAP *R) {
-    // FIXME: Implement.
-    assert(false);
+    if constexpr (Signed)
+      *R = IntegralAP(A.V.sdiv(B.V));
+    else
+      *R = IntegralAP(A.V.udiv(B.V));
     return false;
   }
 
diff --git a/clang/test/AST/Interp/intap.cpp b/clang/test/AST/Interp/intap.cpp
index c93ec331296647b..30cff785fb34cf7 100644
--- a/clang/test/AST/Interp/intap.cpp
+++ b/clang/test/AST/Interp/intap.cpp
@@ -44,6 +44,24 @@ static_assert(MulA * MulB == 50, ""); // ref-error {{not an integral constant ex
 static_assert(MulA * 5 == 25, "");
 static_assert(-1 * MulB == -7, "");
 
+
+constexpr _BitInt(4) DivA = 2;
+constexpr _BitInt(2) DivB = 1;
+static_assert(DivA / DivB == 2, "");
+
+constexpr _BitInt(4) DivC = DivA / 0; // ref-error {{must be initialized by a constant expression}} \
+                                      // ref-note {{division by zero}} \
+                                      // expected-error {{must be initialized by a constant expression}} \
+                                      // expected-note {{division by zero}}
+
+constexpr _BitInt(7) RemA = 47;
+constexpr _BitInt(6) RemB = 9;
+static_assert(RemA % RemB == 2, "");
+static_assert(RemA % 0 == 1, ""); // ref-error {{not an integral constant expression}} \
+                                  // ref-note {{division by zero}} \
+                                  // expected-error {{not an integral constant expression}} \
+                                  // expected-note {{division by zero}}
+
 namespace APCast {
   constexpr _BitInt(10) A = 1;
   constexpr _BitInt(11) B = A;

[tbaederr]

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[tbaederr]

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[AaronBallman]

LGTM aside from a test request.

[AaronBallman]

I'd appreciate another test along the lines of:

constexpr int bottom = -1;
constexpr int top = INT_MIN;
constexpr int nope = top / bottom;
constexpr int noooo = top % bottom;

[tbaederr]

Did you really mean int? Or _BitInt?

[AaronBallman]

I meant int; basically, it's catching the other form of UB that's not division by zero.

[tbaederr]

Using int means it won't use IntegralAP at all though. I've added those tests with _BitInt(32).

[AaronBallman]

Ah, thank you!

[tbaederr]

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[tbaederr]

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[AaronBallman]

LGTM!

[AaronBallman]

Ah, thank you!