[LLVM-C] Upstream LLVMBuild{Min,Max}Num from rustc

[AMS21]

Upstreaming the LLVMBuildMinNum and LLVMBuildMaxNum functions to create calls to the minnum and maxnum intrinsics.

[llvmbot]

@llvm/pr-subscribers-llvm-ir

Author: None (AMS21)

Changes

Upstreaming the LLVMBuildMinNum and LLVMBuildMaxNum functions to create calls to the minnum and maxnum intrinsics.

---

Full diff: https://github.com/llvm/llvm-project/pull/162500.diff

4 Files Affected:

• (modified) llvm/docs/ReleaseNotes.md (+1)
• (modified) llvm/include/llvm-c/Core.h (+20)
• (modified) llvm/lib/IR/Core.cpp (+10)
• (modified) llvm/unittests/IR/InstructionsTest.cpp (+23)

diff --git a/llvm/docs/ReleaseNotes.md b/llvm/docs/ReleaseNotes.md
index 79d93d08b8398..15c9aaf3b129b 100644
--- a/llvm/docs/ReleaseNotes.md
+++ b/llvm/docs/ReleaseNotes.md
@@ -147,6 +147,7 @@ Changes to the C API
 --------------------
 
 * Add `LLVMGetOrInsertFunction` to get or insert a function, replacing the combination of `LLVMGetNamedFunction` and `LLVMAddFunction`.
+* Add `LLVMBuildMinNum` and `LLVMBuildMaxNum` to create calls to the `minnum` and `maxnum` intrinsics.
 
 Changes to the CodeGen infrastructure
 -------------------------------------
diff --git a/llvm/include/llvm-c/Core.h b/llvm/include/llvm-c/Core.h
index 3d22f85911e78..2d66050b5acfa 100644
--- a/llvm/include/llvm-c/Core.h
+++ b/llvm/include/llvm-c/Core.h
@@ -4626,6 +4626,26 @@ LLVM_C_ABI LLVMValueRef LLVMBuildFNeg(LLVMBuilderRef, LLVMValueRef V,
 LLVM_C_ABI LLVMValueRef LLVMBuildNot(LLVMBuilderRef, LLVMValueRef V,
                                      const char *Name);
 
+/**
+ * Creates and inserts a minnum intrinsic intruction.
+ *
+ * Returns the minimum of the two floating point values.
+ *
+ * @see llvm::IRBuilder::CreateMinNum()
+ */
+LLVM_C_ABI LLVMValueRef LLVMBuildMinNum(LLVMBuilderRef B, LLVMValueRef LHS,
+                                        LLVMValueRef RHS);
+
+/**
+ * Creates and inserts a maxnum intrinsic intruction.
+ *
+ * Returns the maximum of the two floating point values.
+ *
+ * @see llvm::IRBuilder::CreateMaxNum()
+ */
+LLVM_C_ABI LLVMValueRef LLVMBuildMaxNum(LLVMBuilderRef B, LLVMValueRef LHS,
+                                        LLVMValueRef RHS);
+
 LLVM_C_ABI LLVMBool LLVMGetNUW(LLVMValueRef ArithInst);
 LLVM_C_ABI void LLVMSetNUW(LLVMValueRef ArithInst, LLVMBool HasNUW);
 LLVM_C_ABI LLVMBool LLVMGetNSW(LLVMValueRef ArithInst);
diff --git a/llvm/lib/IR/Core.cpp b/llvm/lib/IR/Core.cpp
index 3f1cc1e4e6d0e..d0285fb4516fa 100644
--- a/llvm/lib/IR/Core.cpp
+++ b/llvm/lib/IR/Core.cpp
@@ -3804,6 +3804,16 @@ LLVMValueRef LLVMBuildNot(LLVMBuilderRef B, LLVMValueRef V, const char *Name) {
   return wrap(unwrap(B)->CreateNot(unwrap(V), Name));
 }
 
+LLVMValueRef LLVMBuildMinNum(LLVMBuilderRef B, LLVMValueRef LHS,
+                             LLVMValueRef RHS) {
+  return wrap(unwrap(B)->CreateMinNum(unwrap(LHS), unwrap(RHS)));
+}
+
+LLVMValueRef LLVMBuildMaxNum(LLVMBuilderRef B, LLVMValueRef LHS,
+                             LLVMValueRef RHS) {
+  return wrap(unwrap(B)->CreateMaxNum(unwrap(LHS), unwrap(RHS)));
+}
+
 LLVMBool LLVMGetNUW(LLVMValueRef ArithInst) {
   Value *P = unwrap<Value>(ArithInst);
   return cast<Instruction>(P)->hasNoUnsignedWrap();
diff --git a/llvm/unittests/IR/InstructionsTest.cpp b/llvm/unittests/IR/InstructionsTest.cpp
index fe9e7e8228490..cb79a14d0ee7f 100644
--- a/llvm/unittests/IR/InstructionsTest.cpp
+++ b/llvm/unittests/IR/InstructionsTest.cpp
@@ -1933,5 +1933,28 @@ TEST(InstructionsTest, StripAndAccumulateConstantOffset) {
   EXPECT_TRUE(Offset.isZero());
 }
 
+TEST(InstructionsTest, LLVMBuildMinMaxNum) {
+  LLVMContext Ctx;
+  Module M("Mod", Ctx);
+  FunctionType *FT = FunctionType::get(Type::getVoidTy(Ctx), {}, false);
+  Function *F = Function::Create(FT, Function::ExternalLinkage, "f", M);
+  BasicBlock *BB = BasicBlock::Create(Ctx, "entry", F);
+  IRBuilder<> B(BB);
+
+  Type *FTy = B.getFloatTy();
+  Value *LHS = ConstantFP::get(FTy, 1.0);
+  Value *RHS = ConstantFP::get(FTy, 2.0);
+
+  auto *Min = unwrap<CallInst>(LLVMBuildMinNum(wrap(&B), wrap(LHS), wrap(RHS)));
+  Function *MinFunc = Min->getCalledFunction();
+  EXPECT_EQ(MinFunc->getIntrinsicID(), Intrinsic::minnum);
+  EXPECT_EQ(Min->getType(), FTy);
+
+  auto *Max = unwrap<CallInst>(LLVMBuildMaxNum(wrap(&B), wrap(LHS), wrap(RHS)));
+  Function *MaxFunc = Max->getCalledFunction();
+  EXPECT_EQ(MaxFunc->getIntrinsicID(), Intrinsic::maxnum);
+  EXPECT_EQ(Max->getType(), FTy);
+}
+
 } // end anonymous namespace
 } // end namespace llvm

[nikic]

I'm not sure why we have these functions on the Rust side at all. minnum and maxnum are just normal intrinsics, so we should just do something like self.call_intrinsic("llvm.minnum", &[self.val_ty(lhs)], &[lhs, rhs]).

[nikic]

This also applies to all the LLVMRustBuildVectorReduceXYZ functions.

[AMS21]

I'm not sure why we have these functions on the Rust side at all. minnum and maxnum are just normal intrinsics, so we should just do something like self.call_intrinsic("llvm.minnum", &[self.val_ty(lhs)], &[lhs, rhs]).
This also applies to all the LLVMRustBuildVectorReduceXYZ functions.

Good question. Seems like they were added 8 Years ago with rust-lang/rust@7d5343a and rust-lang/rust@01cc5b3.
I'll close this and refactor this on the rust side instead :)