diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp --- a/llvm/lib/Target/X86/X86FrameLowering.cpp +++ b/llvm/lib/Target/X86/X86FrameLowering.cpp @@ -3009,6 +3009,12 @@ I = MBB.erase(I); auto InsertPos = skipDebugInstructionsForward(I, MBB.end()); + // Try to avoid emitting dead SP adjustments if the block end is unreachable, + // typically because the function is marked noreturn (abort, throw, + // assert_fail, etc). + if (isDestroy && blockEndIsUnreachable(MBB, I)) + return I; + if (!reserveCallFrame) { // If the stack pointer can be changed after prologue, turn the // adjcallstackup instruction into a 'sub ESP, ' and the @@ -3091,13 +3097,7 @@ return I; } - if (isDestroy && InternalAmt && !blockEndIsUnreachable(MBB, I)) { - // If we are performing frame pointer elimination and if the callee pops - // something off the stack pointer, add it back. We do this until we have - // more advanced stack pointer tracking ability. - // We are not tracking the stack pointer adjustment by the callee, so make - // sure we restore the stack pointer immediately after the call, there may - // be spill code inserted between the CALL and ADJCALLSTACKUP instructions. + if (InternalAmt) { MachineBasicBlock::iterator CI = I; MachineBasicBlock::iterator B = MBB.begin(); while (CI != B && !std::prev(CI)->isCall()) diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -4362,12 +4362,6 @@ else NumBytesForCalleeToPop = 0; // Callee pops nothing. - if (CLI.DoesNotReturn && !getTargetMachine().Options.TrapUnreachable) { - // No need to reset the stack after the call if the call doesn't return. To - // make the MI verify, we'll pretend the callee does it for us. - NumBytesForCalleeToPop = NumBytes; - } - // Returns a flag for retval copy to use. if (!IsSibcall) { Chain = DAG.getCALLSEQ_END(Chain, diff --git a/llvm/test/CodeGen/X86/noreturn-call-win64.ll b/llvm/test/CodeGen/X86/noreturn-call-win64.ll --- a/llvm/test/CodeGen/X86/noreturn-call-win64.ll +++ b/llvm/test/CodeGen/X86/noreturn-call-win64.ll @@ -1,5 +1,8 @@ ; RUN: llc < %s -mtriple=x86_64-windows-msvc | FileCheck %s +%struct.MakeCleanup = type { i8 } +%eh.ThrowInfo = type { i32, i32, i32, i32 } + ; Function Attrs: noinline nounwind optnone uwtable define dso_local i32 @foo() { entry: @@ -51,3 +54,58 @@ declare dso_local void @abort1() noreturn declare dso_local void @abort2() noreturn declare dso_local void @abort3() noreturn + +define dso_local void @throw_exception() uwtable personality i32 (...)* @__CxxFrameHandler3 { +entry: + %o = alloca %struct.MakeCleanup, align 1 + %call = invoke i32 @cond() + to label %invoke.cont unwind label %ehcleanup + +invoke.cont: ; preds = %entry + %cmp1 = icmp eq i32 0, %call + br i1 %cmp1, label %if.then, label %if.end + +if.then: ; preds = %invoke.cont + invoke void @_CxxThrowException(i8* null, %eh.ThrowInfo* null) + to label %unreachable unwind label %ehcleanup + +if.end: ; preds = %invoke.cont + %call2 = invoke i32 @cond() + to label %invoke.cont1 unwind label %ehcleanup + +invoke.cont1: ; preds = %if.end + %cmp2 = icmp eq i32 0, %call2 + br i1 %cmp2, label %if.then3, label %if.end4 + +if.then3: ; preds = %invoke.cont1 + invoke void @_CxxThrowException(i8* null, %eh.ThrowInfo* null) + to label %unreachable unwind label %ehcleanup + +if.end4: ; preds = %invoke.cont1 + call void @"??1MakeCleanup@@QEAA@XZ"(%struct.MakeCleanup* nonnull %o) + ret void + +ehcleanup: ; preds = %if.then3, %if.end, %if.then, %entry + %cp = cleanuppad within none [] + call void @"??1MakeCleanup@@QEAA@XZ"(%struct.MakeCleanup* nonnull %o) [ "funclet"(token %cp) ] + cleanupret from %cp unwind to caller + +unreachable: ; preds = %if.then3, %if.then + unreachable +} + +declare dso_local i32 @__CxxFrameHandler3(...) +declare dso_local void @_CxxThrowException(i8*, %eh.ThrowInfo*) +declare dso_local void @"??1MakeCleanup@@QEAA@XZ"(%struct.MakeCleanup*) + +; CHECK-LABEL: throw_exception: +; CHECK: callq cond +; CHECK: je +; CHECK: callq cond +; CHECK: je +; CHECK: retq +; CHECK: callq _CxxThrowException +; CHECK-NOT: {{(addq|subq) .*, %rsp}} +; CHECK: callq _CxxThrowException +; CHECK-NOT: {{(addq|subq) .*, %rsp}} +; CHECK: .seh_handlerdata