diff --git a/llvm/lib/CodeGen/MachineSink.cpp b/llvm/lib/CodeGen/MachineSink.cpp index 8409c95f0ec7297..d782c8b08631935 100644 --- a/llvm/lib/CodeGen/MachineSink.cpp +++ b/llvm/lib/CodeGen/MachineSink.cpp @@ -961,7 +961,7 @@ bool MachineSinking::isLegalToBreakCriticalEdge(MachineInstr &MI, MachineBasicBlock *ToBB, bool BreakPHIEdge) { // Avoid breaking back edge. From == To means backedge for single BB cycle. - if (!SplitEdges || FromBB == ToBB) + if (!SplitEdges || FromBB == ToBB || !FromBB->isSuccessor(ToBB)) return false; MachineCycle *FromCycle = CI->getCycle(FromBB); diff --git a/llvm/test/CodeGen/X86/MachineSink-Issue98477.ll b/llvm/test/CodeGen/X86/MachineSink-Issue98477.ll new file mode 100644 index 000000000000000..4df32854cdae441 --- /dev/null +++ b/llvm/test/CodeGen/X86/MachineSink-Issue98477.ll @@ -0,0 +1,76 @@ +; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5 +; RUN: llc < %s | FileCheck %s + +target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +define i32 @main(i1 %tobool.not, i32 %0) { +; CHECK-LABEL: main: +; CHECK: # %bb.0: # %entry +; CHECK-NEXT: movl $1, %r8d +; CHECK-NEXT: testb $1, %dil +; CHECK-NEXT: jne .LBB0_8 +; CHECK-NEXT: .LBB0_1: # %j.preheader +; CHECK-NEXT: xorl %r9d, %r9d +; CHECK-NEXT: jmp .LBB0_2 +; CHECK-NEXT: .p2align 4, 0x90 +; CHECK-NEXT: .LBB0_5: # %if.then4 +; CHECK-NEXT: # in Loop: Header=BB0_2 Depth=1 +; CHECK-NEXT: movl $1, %eax +; CHECK-NEXT: xorl %edx, %edx +; CHECK-NEXT: divl %r8d +; CHECK-NEXT: testb $1, %dil +; CHECK-NEXT: jne .LBB0_6 +; CHECK-NEXT: .LBB0_2: # %j +; CHECK-NEXT: # =>This Inner Loop Header: Depth=1 +; CHECK-NEXT: movl $1, %eax +; CHECK-NEXT: xorl %edx, %edx +; CHECK-NEXT: idivl %esi +; CHECK-NEXT: movl %edx, %ecx +; CHECK-NEXT: testb %r9b, %r9b +; CHECK-NEXT: jne .LBB0_5 +; CHECK-NEXT: # %bb.3: # %j +; CHECK-NEXT: # in Loop: Header=BB0_2 Depth=1 +; CHECK-NEXT: testl %r9d, %r9d +; CHECK-NEXT: js .LBB0_5 +; CHECK-NEXT: # %bb.4: +; CHECK-NEXT: movl %r9d, %edx +; CHECK-NEXT: .LBB0_6: # %if.end9 +; CHECK-NEXT: testl %edx, %edx +; CHECK-NEXT: jne .LBB0_7 +; CHECK-NEXT: .LBB0_8: # %if.end13 +; CHECK-NEXT: xorl %r8d, %r8d +; CHECK-NEXT: jmp .LBB0_1 +; CHECK-NEXT: .LBB0_7: # %while.body.lr.ph +; CHECK-NEXT: movl %ecx, %eax +; CHECK-NEXT: retq +entry: + br i1 %tobool.not, label %if.end13, label %j.preheader + + j.preheader: ; preds = %if.end13, %entry + %h.0.ph = phi i32 [ 1, %entry ], [ 0, %if.end13 ] + br label %j + + j: ; preds = %if.then4, %j.preheader + %1 = phi i32 [ %div2, %if.then4 ], [ 0, %j.preheader ] + %rem1 = srem i32 1, %0 + %cmp = icmp slt i32 %1, 0 + %or.cond = select i1 false, i1 true, i1 %cmp + br i1 %or.cond, label %if.then4, label %if.end9 + + if.then4: ; preds = %j + %div2 = sdiv i32 1, 0 + %rem5 = srem i32 1, %h.0.ph + br i1 %tobool.not, label %if.end9, label %j + + if.end9: ; preds = %if.then4, %j + %2 = phi i32 [ 0, %j ], [ %rem5, %if.then4 ] + %tobool10.not = icmp eq i32 %2, 0 + br i1 %tobool10.not, label %if.end13, label %while.body.lr.ph + + while.body.lr.ph: ; preds = %if.end9 + ret i32 %rem1 + + if.end13: ; preds = %if.end9, %entry + br label %j.preheader +}