Index: lib/Target/Mips/Mips.td =================================================================== --- lib/Target/Mips/Mips.td +++ lib/Target/Mips/Mips.td @@ -188,6 +188,9 @@ def FeatureMadd4 : SubtargetFeature<"nomadd4", "DisableMadd4", "true", "Disable 4-operand madd.fmt and related instructions">; +def FeatureLongCalls : SubtargetFeature<"long-calls", "UseLongCalls", "true", + "Disable use of the jal instruction">; + //===----------------------------------------------------------------------===// // Mips processors supported. //===----------------------------------------------------------------------===// Index: lib/Target/Mips/MipsISelLowering.cpp =================================================================== --- lib/Target/Mips/MipsISelLowering.cpp +++ lib/Target/Mips/MipsISelLowering.cpp @@ -3021,6 +3021,15 @@ EVT Ty = Callee.getValueType(); bool GlobalOrExternal = false, IsCallReloc = false; + if (Subtarget.useLongCalls() && Subtarget.hasSym32() && !IsPIC) { + // Get the address of the callee into a register to prevent + // using of the `jal` instruction for the direct call. + if (auto *N = dyn_cast(Callee)) + Callee = getAddrNonPIC(N, SDLoc(N), Ty, DAG); + else if (auto *N = dyn_cast(Callee)) + Callee = getAddrNonPIC(N, SDLoc(N), Ty, DAG); + } + if (GlobalAddressSDNode *G = dyn_cast(Callee)) { if (IsPIC) { const GlobalValue *Val = G->getGlobal(); Index: lib/Target/Mips/MipsSubtarget.h =================================================================== --- lib/Target/Mips/MipsSubtarget.h +++ lib/Target/Mips/MipsSubtarget.h @@ -149,6 +149,9 @@ // related instructions. bool DisableMadd4; + // Disable use of the `jal` instruction. + bool UseLongCalls = false; + InstrItineraryData InstrItins; // We can override the determination of whether we are in mips16 mode @@ -265,6 +268,8 @@ bool useSoftFloat() const { return IsSoftFloat; } + bool useLongCalls() const { return UseLongCalls; } + bool enableLongBranchPass() const { return hasStandardEncoding() || allowMixed16_32(); } Index: test/CodeGen/Mips/long-calls.ll =================================================================== --- /dev/null +++ test/CodeGen/Mips/long-calls.ll @@ -0,0 +1,31 @@ +; RUN: llc -march=mips -mattr=-long-calls %s -o - \ +; RUN: | FileCheck -check-prefix=OFF %s +; RUN: llc -march=mips -mattr=+long-calls %s -o - \ +; RUN: | FileCheck -check-prefix=ON %s + +declare void @callee() +declare void @llvm.memset.p0i8.i32(i8* nocapture writeonly, i8, i32, i32, i1) + +@val = internal unnamed_addr global [20 x i32] zeroinitializer, align 4 + +define void @caller() { + +; Use `jal` instruction with R_MIPS_26 relocation. +; OFF: jal callee +; OFF: jal memset + +; Save the `callee` and `memset` addresses in $25 register +; and use `jalr` for the jumps. +; ON: lui $1, %hi(callee) +; ON: addiu $25, $1, %lo(callee) +; ON: jalr $25 + +; ON: addiu $1, $zero, %lo(memset) +; ON: lui $2, %hi(memset) +; ON: addu $25, $2, $1 +; ON: jalr $25 + + call void @callee() + call void @llvm.memset.p0i8.i32(i8* bitcast ([20 x i32]* @val to i8*), i8 0, i32 80, i32 4, i1 false) + ret void +}