llvm · frederik-h · Dec 18, 2025 · Dec 17, 2025
diff --git a/llvm/docs/WritingAnLLVMPass.rst b/llvm/docs/WritingAnLLVMPass.rst
@@ -673,7 +673,7 @@ default optimization pipelines, e.g. (the output has been trimmed):
   ModulePass Manager
   Pre-ISel Intrinsic Lowering
   FunctionPass Manager
-    Expand fp
+    Expand IR instructions
     Expand Atomic instructions
   SVE intrinsics optimizations
     FunctionPass Manager

diff --git a/llvm/include/llvm/CodeGen/ExpandFp.h → llvm/include/llvm/CodeGen/ExpandIRInsts.h b/llvm/include/llvm/CodeGen/ExpandFp.h → llvm/include/llvm/CodeGen/ExpandIRInsts.h
@@ -1,13 +1,13 @@
-//===- ExpandFp.h -----------------------------------*- C++ -*-===//
+//===- ExpandIRInsts.h -----------------------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_CODEGEN_EXPANDFP_H
-#define LLVM_CODEGEN_EXPANDFP_H
+#ifndef LLVM_CODEGEN_EXPANDIRINSTS_H
+#define LLVM_CODEGEN_EXPANDIRINSTS_H
 
 #include "llvm/IR/PassManager.h"
 #include "llvm/Support/CodeGen.h"
@@ -16,13 +16,13 @@ namespace llvm {
 
 class TargetMachine;
 
-class ExpandFpPass : public PassInfoMixin<ExpandFpPass> {
+class ExpandIRInstsPass : public PassInfoMixin<ExpandIRInstsPass> {
 private:
   const TargetMachine *TM;
   CodeGenOptLevel OptLevel;
 
 public:
-  explicit ExpandFpPass(const TargetMachine &TM, CodeGenOptLevel OptLevel);
+  explicit ExpandIRInstsPass(const TargetMachine &TM, CodeGenOptLevel OptLevel);
 
   PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
   static bool isRequired() { return true; }
@@ -32,4 +32,4 @@ class ExpandFpPass : public PassInfoMixin<ExpandFpPass> {
 
 } // end namespace llvm
 
-#endif // LLVM_CODEGEN_EXPANDFP_H
+#endif // LLVM_CODEGEN_EXPANDIRINSTS_H
diff --git a/llvm/include/llvm/CodeGen/Passes.h b/llvm/include/llvm/CodeGen/Passes.h
@@ -547,7 +547,7 @@ LLVM_ABI FunctionPass *createExpandReductionsPass();
 LLVM_ABI FunctionPass *createReplaceWithVeclibLegacyPass();
 
 // Expands large div/rem instructions.
-LLVM_ABI FunctionPass *createExpandFpPass();
+LLVM_ABI FunctionPass *createExpandIRInstsPass();
 
 // This pass expands memcmp() to load/stores.
 LLVM_ABI FunctionPass *createExpandMemCmpLegacyPass();
@@ -565,7 +565,7 @@ LLVM_ABI FunctionPass *createCFIFixup();
 LLVM_ABI FunctionPass *createCFIInstrInserter();
 
 // Expands floating point instructions.
-FunctionPass *createExpandFpPass(CodeGenOptLevel);
+FunctionPass *createExpandIRInstsPass(CodeGenOptLevel);
 
 /// Creates CFGuard longjmp target identification pass.
 /// \see CFGuardLongjmp.cpp

diff --git a/llvm/include/llvm/CodeGen/TargetLowering.h b/llvm/include/llvm/CodeGen/TargetLowering.h
@@ -2219,13 +2219,13 @@ class LLVM_ABI TargetLoweringBase {
   }
 
   /// Returns the size in bits of the maximum div/rem the backend supports.
-  /// Larger operations will be expanded by ExpandFp.
+  /// Larger operations will be expanded by ExpandIRInsts.
   unsigned getMaxDivRemBitWidthSupported() const {
     return MaxDivRemBitWidthSupported;
   }
 
   /// Returns the size in bits of the maximum fp to/from int conversion the
-  /// backend supports. Larger operations will be expanded by ExpandFp.
+  /// backend supports. Larger operations will be expanded by ExpandIRInsts.
   unsigned getMaxLargeFPConvertBitWidthSupported() const {
     return MaxLargeFPConvertBitWidthSupported;
   }
@@ -2885,13 +2885,13 @@ class LLVM_ABI TargetLoweringBase {
   }
 
   /// Set the size in bits of the maximum div/rem the backend supports.
-  /// Larger operations will be expanded by ExpandFp.
+  /// Larger operations will be expanded by ExpandIRInsts.
   void setMaxDivRemBitWidthSupported(unsigned SizeInBits) {
     MaxDivRemBitWidthSupported = SizeInBits;
   }
 
   /// Set the size in bits of the maximum fp to/from int conversion the backend
-  /// supports. Larger operations will be expanded by ExpandFp.
+  /// supports. Larger operations will be expanded by ExpandIRInsts.
   void setMaxLargeFPConvertBitWidthSupported(unsigned SizeInBits) {
     MaxLargeFPConvertBitWidthSupported = SizeInBits;
   }
@@ -3742,12 +3742,12 @@ class LLVM_ABI TargetLoweringBase {
   unsigned MaxAtomicSizeInBitsSupported;
 
   /// Size in bits of the maximum div/rem size the backend supports.
-  /// Larger operations will be expanded by ExpandFp.
+  /// Larger operations will be expanded by ExpandIRInsts.
   unsigned MaxDivRemBitWidthSupported;
 
   /// Size in bits of the maximum fp to/from int conversion size the
   /// backend supports. Larger operations will be expanded by
-  /// ExpandFp.
+  /// ExpandIRInsts.
   unsigned MaxLargeFPConvertBitWidthSupported;
 
   /// Size in bits of the minimum cmpxchg or ll/sc operation the

diff --git a/llvm/include/llvm/InitializePasses.h b/llvm/include/llvm/InitializePasses.h
@@ -112,7 +112,7 @@ LLVM_ABI void initializeEarlyMachineLICMPass(PassRegistry &);
 LLVM_ABI void initializeEarlyTailDuplicateLegacyPass(PassRegistry &);
 LLVM_ABI void initializeEdgeBundlesWrapperLegacyPass(PassRegistry &);
 LLVM_ABI void initializeEHContGuardTargetsPass(PassRegistry &);
-LLVM_ABI void initializeExpandFpLegacyPassPass(PassRegistry &);
+LLVM_ABI void initializeExpandIRInstsLegacyPassPass(PassRegistry &);
 LLVM_ABI void initializeExpandMemCmpLegacyPassPass(PassRegistry &);
 LLVM_ABI void initializeExpandPostRALegacyPass(PassRegistry &);
 LLVM_ABI void initializeExpandReductionsPass(PassRegistry &);

diff --git a/llvm/include/llvm/Passes/CodeGenPassBuilder.h b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
@@ -32,7 +32,7 @@
 #include "llvm/CodeGen/DetectDeadLanes.h"
 #include "llvm/CodeGen/DwarfEHPrepare.h"
 #include "llvm/CodeGen/EarlyIfConversion.h"
-#include "llvm/CodeGen/ExpandFp.h"
+#include "llvm/CodeGen/ExpandIRInsts.h"
 #include "llvm/CodeGen/ExpandMemCmp.h"
 #include "llvm/CodeGen/ExpandPostRAPseudos.h"
 #include "llvm/CodeGen/ExpandReductions.h"
@@ -677,7 +677,7 @@ void CodeGenPassBuilder<Derived, TargetMachineT>::addISelPasses(
     addModulePass(LowerEmuTLSPass(), PMW);
 
   addModulePass(PreISelIntrinsicLoweringPass(&TM), PMW);
-  addFunctionPass(ExpandFpPass(TM, getOptLevel()), PMW);
+  addFunctionPass(ExpandIRInstsPass(TM, getOptLevel()), PMW);
 
   derived().addIRPasses(PMW);
   derived().addCodeGenPrepare(PMW);

diff --git a/llvm/lib/CodeGen/CMakeLists.txt b/llvm/lib/CodeGen/CMakeLists.txt
@@ -57,7 +57,7 @@ add_llvm_component_library(LLVMCodeGen
   EdgeBundles.cpp
   EHContGuardTargets.cpp
   ExecutionDomainFix.cpp
-  ExpandFp.cpp
+  ExpandIRInsts.cpp
   ExpandMemCmp.cpp
   ExpandPostRAPseudos.cpp
   ExpandReductions.cpp

diff --git a/llvm/lib/CodeGen/CodeGen.cpp b/llvm/lib/CodeGen/CodeGen.cpp
@@ -39,7 +39,7 @@ void llvm::initializeCodeGen(PassRegistry &Registry) {
   initializeEarlyIfPredicatorPass(Registry);
   initializeEarlyMachineLICMPass(Registry);
   initializeEarlyTailDuplicateLegacyPass(Registry);
-  initializeExpandFpLegacyPassPass(Registry);
+  initializeExpandIRInstsLegacyPassPass(Registry);
   initializeExpandMemCmpLegacyPassPass(Registry);
   initializeExpandPostRALegacyPass(Registry);
   initializeFEntryInserterLegacyPass(Registry);

diff --git a/llvm/lib/CodeGen/ExpandFp.cpp → llvm/lib/CodeGen/ExpandIRInsts.cpp b/llvm/lib/CodeGen/ExpandFp.cpp → llvm/lib/CodeGen/ExpandIRInsts.cpp
@@ -1,26 +1,33 @@
-//===--- ExpandFp.cpp - Expand fp instructions ----------------------------===//
+//===--- ExpandIRInsts.cpp - Expand IR instructions -----------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
-// This pass expands certain floating point instructions at the IR level.
+// This pass expands certain instructions at the IR level.
 //
-// It expands ‘fptoui .. to’, ‘fptosi .. to’, ‘uitofp ..  to’, ‘sitofp
+// The following expansions are implemented:
+// - Expansion of ‘fptoui .. to’, ‘fptosi .. to’, ‘uitofp ..  to’, ‘sitofp
 // .. to’ instructions with a bitwidth above a threshold.  This is
 // useful for targets like x86_64 that cannot lower fp convertions
 // with more than 128 bits.
 //
-// This pass also expands div/rem instructions with a bitwidth above a
-// threshold into a call to auto-generated functions.  This is useful
-// for targets like x86_64 that cannot lower divisions with more than
-// 128 bits or targets like x86_32 that cannot lower divisions with
-// more than 64 bits.
+// - Expansion of ‘frem‘ for types MVT::f16, MVT::f32, and MVT::f64 for
+// targets which use "Expand" as the legalization action for the
+// corresponding type.
 //
+// - Expansion of ‘udiv‘, ‘sdiv‘, ‘urem‘, and ‘srem‘ instructions with
+// a bitwidth above a threshold into a call to auto-generated
+// functions.  This is useful for targets like x86_64 that cannot
+// lower divisions with more than 128 bits or targets like x86_32 that
+// cannot lower divisions with more than 64 bits.
+//
+// Instructions with vector types are scalarized first if their scalar
+// types can be expanded. Scalable vector types are not supported.
 //===----------------------------------------------------------------------===//
 
-#include "llvm/CodeGen/ExpandFp.h"
+#include "llvm/CodeGen/ExpandIRInsts.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/Analysis/GlobalsModRef.h"
@@ -45,7 +52,7 @@
 #include <llvm/Support/Casting.h>
 #include <optional>
 
-#define DEBUG_TYPE "expand-fp"
+#define DEBUG_TYPE "expand-ir-insts"
 
 using namespace llvm;
 
@@ -1125,18 +1132,18 @@ static bool runImpl(Function &F, const TargetLowering &TLI,
 }
 
 namespace {
-class ExpandFpLegacyPass : public FunctionPass {
+class ExpandIRInstsLegacyPass : public FunctionPass {
   CodeGenOptLevel OptLevel;
 
 public:
   static char ID;
 
-  ExpandFpLegacyPass(CodeGenOptLevel OptLevel)
+  ExpandIRInstsLegacyPass(CodeGenOptLevel OptLevel)
       : FunctionPass(ID), OptLevel(OptLevel) {
-    initializeExpandFpLegacyPassPass(*PassRegistry::getPassRegistry());
+    initializeExpandIRInstsLegacyPassPass(*PassRegistry::getPassRegistry());
   }
 
-  ExpandFpLegacyPass() : ExpandFpLegacyPass(CodeGenOptLevel::None) {};
+  ExpandIRInstsLegacyPass() : ExpandIRInstsLegacyPass(CodeGenOptLevel::None) {};
 
   bool runOnFunction(Function &F) override {
     auto *TM = &getAnalysis<TargetPassConfig>().getTM<TargetMachine>();
@@ -1165,19 +1172,21 @@ class ExpandFpLegacyPass : public FunctionPass {
 };
 } // namespace
 
-ExpandFpPass::ExpandFpPass(const TargetMachine &TM, CodeGenOptLevel OptLevel)
+ExpandIRInstsPass::ExpandIRInstsPass(const TargetMachine &TM,
+                                     CodeGenOptLevel OptLevel)
     : TM(&TM), OptLevel(OptLevel) {}
 
-void ExpandFpPass::printPipeline(
+void ExpandIRInstsPass::printPipeline(
     raw_ostream &OS, function_ref<StringRef(StringRef)> MapClassName2PassName) {
-  static_cast<PassInfoMixin<ExpandFpPass> *>(this)->printPipeline(
+  static_cast<PassInfoMixin<ExpandIRInstsPass> *>(this)->printPipeline(
       OS, MapClassName2PassName);
   OS << '<';
   OS << "O" << (int)OptLevel;
   OS << '>';
 }
 
-PreservedAnalyses ExpandFpPass::run(Function &F, FunctionAnalysisManager &FAM) {
+PreservedAnalyses ExpandIRInstsPass::run(Function &F,
+                                         FunctionAnalysisManager &FAM) {
   const TargetSubtargetInfo *STI = TM->getSubtargetImpl(F);
   auto &TLI = *STI->getTargetLowering();
   AssumptionCache *AC = nullptr;
@@ -1202,12 +1211,13 @@ PreservedAnalyses ExpandFpPass::run(Function &F, FunctionAnalysisManager &FAM) {
                                        : PreservedAnalyses::all();
 }
 
-char ExpandFpLegacyPass::ID = 0;
-INITIALIZE_PASS_BEGIN(ExpandFpLegacyPass, "expand-fp",
+char ExpandIRInstsLegacyPass::ID = 0;
+INITIALIZE_PASS_BEGIN(ExpandIRInstsLegacyPass, "expand-ir-insts",
                       "Expand certain fp instructions", false, false)
 INITIALIZE_PASS_DEPENDENCY(LibcallLoweringInfoWrapper)
-INITIALIZE_PASS_END(ExpandFpLegacyPass, "expand-fp", "Expand fp", false, false)
+INITIALIZE_PASS_END(ExpandIRInstsLegacyPass, "expand-ir-insts",
+                    "Expand IR instructions", false, false)
 
-FunctionPass *llvm::createExpandFpPass(CodeGenOptLevel OptLevel) {
-  return new ExpandFpLegacyPass(OptLevel);
+FunctionPass *llvm::createExpandIRInstsPass(CodeGenOptLevel OptLevel) {
+  return new ExpandIRInstsLegacyPass(OptLevel);
 }
diff --git a/llvm/lib/CodeGen/TargetPassConfig.cpp b/llvm/lib/CodeGen/TargetPassConfig.cpp
@@ -1090,7 +1090,7 @@ bool TargetPassConfig::addISelPasses() {
 
   PM->add(createTargetTransformInfoWrapperPass(TM->getTargetIRAnalysis()));
   addPass(createPreISelIntrinsicLoweringPass());
-  addPass(createExpandFpPass(getOptLevel()));
+  addPass(createExpandIRInstsPass(getOptLevel()));
   addIRPasses();
   addCodeGenPrepare();
   addPassesToHandleExceptions();

diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
@@ -91,7 +91,7 @@
 #include "llvm/CodeGen/DwarfEHPrepare.h"
 #include "llvm/CodeGen/EarlyIfConversion.h"
 #include "llvm/CodeGen/EdgeBundles.h"
-#include "llvm/CodeGen/ExpandFp.h"
+#include "llvm/CodeGen/ExpandIRInsts.h"
 #include "llvm/CodeGen/ExpandMemCmp.h"
 #include "llvm/CodeGen/ExpandPostRAPseudos.h"
 #include "llvm/CodeGen/ExpandReductions.h"
@@ -1632,7 +1632,7 @@ parseBoundsCheckingOptions(StringRef Params) {
   return Options;
 }
 
-Expected<CodeGenOptLevel> parseExpandFpOptions(StringRef Param) {
+Expected<CodeGenOptLevel> parseExpandIRInstsOptions(StringRef Param) {
   if (Param.empty())
     return CodeGenOptLevel::None;
 
@@ -1641,13 +1641,13 @@ Expected<CodeGenOptLevel> parseExpandFpOptions(StringRef Param) {
 
   uint8_t N;
   if (!Prefix.empty() || Digit.getAsInteger(10, N))
-    return createStringError("invalid expand-fp pass parameter '%s'",
+    return createStringError("invalid expand-ir-insts pass parameter '%s'",
                              Param.str().c_str());
 
   std::optional<CodeGenOptLevel> Level = CodeGenOpt::getLevel(N);
   if (!Level.has_value())
     return createStringError(
-        "invalid optimization level for expand-fp pass: %s",
+        "invalid optimization level for expand-ir-insts pass: %s",
         Digit.str().c_str());
 
   return *Level;

diff --git a/llvm/lib/Passes/PassRegistry.def b/llvm/lib/Passes/PassRegistry.def
@@ -729,11 +729,11 @@ FUNCTION_PASS_WITH_PARAMS(
     parseBoundsCheckingOptions,
     "trap;rt;rt-abort;min-rt;min-rt-abort;merge;guard=N")
 FUNCTION_PASS_WITH_PARAMS(
-    "expand-fp", "ExpandFpPass",
+    "expand-ir-insts", "ExpandIRInstsPass",
     [TM = TM](CodeGenOptLevel OL) {
-      return ExpandFpPass(*TM, OL);
+      return ExpandIRInstsPass(*TM, OL);
     },
-    parseExpandFpOptions, "O0;O1;O2;O3")
+    parseExpandIRInstsOptions, "O0;O1;O2;O3")
 
 #undef FUNCTION_PASS_WITH_PARAMS
 

diff --git a/llvm/test/CodeGen/AArch64/O0-pipeline.ll b/llvm/test/CodeGen/AArch64/O0-pipeline.ll
@@ -17,7 +17,7 @@
 ; CHECK-NEXT:   ModulePass Manager
 ; CHECK-NEXT:     Pre-ISel Intrinsic Lowering
 ; CHECK-NEXT:     FunctionPass Manager
-; CHECK-NEXT:       Expand fp
+; CHECK-NEXT:       Expand IR instructions
 ; CHECK-NEXT:       Expand Atomic instructions
 ; CHECK-NEXT:       Module Verifier
 ; CHECK-NEXT:       Lower Garbage Collection Instructions

diff --git a/llvm/test/CodeGen/AArch64/O3-pipeline.ll b/llvm/test/CodeGen/AArch64/O3-pipeline.ll
@@ -21,7 +21,7 @@
 ; CHECK-NEXT:   ModulePass Manager
 ; CHECK-NEXT:     Pre-ISel Intrinsic Lowering
 ; CHECK-NEXT:     FunctionPass Manager
-; CHECK-NEXT:       Expand fp
+; CHECK-NEXT:       Expand IR instructions
 ; CHECK-NEXT:       Expand Atomic instructions
 ; CHECK-NEXT:     SVE intrinsics optimizations
 ; CHECK-NEXT:       FunctionPass Manager

diff --git a/llvm/test/CodeGen/AMDGPU/dagcombine-select.ll b/llvm/test/CodeGen/AMDGPU/dagcombine-select.ll
@@ -579,8 +579,8 @@ define amdgpu_kernel void @fdiv_constant_sel_constants(ptr addrspace(1) %p, i1 %
   ret void
 }
 
-; ExpandFp now expands frem before it reaches dagcombine.
-; TODO Implement this optimization in/before ExpandFP
+; ExpandIRInsts now expands frem before it reaches dagcombine.
+; TODO Implement this optimization in/before ExpandIRInsts?
 define amdgpu_kernel void @frem_constant_sel_constants(ptr addrspace(1) %p, i1 %cond) {
 ; GFX9-LABEL: frem_constant_sel_constants:
 ; GFX9:       ; %bb.0:

diff --git a/llvm/test/CodeGen/AMDGPU/itofp.i128.bf.ll b/llvm/test/CodeGen/AMDGPU/itofp.i128.bf.ll
@@ -2,7 +2,7 @@
 ; RUN: llc -global-isel=0 -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 < %s | FileCheck -check-prefixes=GCN,SDAG %s
 ; RUN: not --crash llc -global-isel=1 -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 < %s 2>&1 | FileCheck -check-prefix=GISEL %s
 
-; FIXME: GISEL can't handle the "fptrunc float to bfloat" that expand-fp emits.
+; FIXME: GISEL can't handle the "fptrunc float to bfloat" that expand-ir-insts emits.
 
 ; GISEL: unable to translate instruction: fptrunc