[llvm] c1b7460 - Revert "RegAlloc: do not consider liveins to EH-pad successors as liveout."

[Tim Northover via llvm-commits]

Author: Tim Northover
Date: 2021-04-29T20:00:07+01:00
New Revision: c1b7460b5b705d983ac40ac37449911d132c7db4

URL: https://github.com/llvm/llvm-project/commit/c1b7460b5b705d983ac40ac37449911d132c7db4
DIFF: https://github.com/llvm/llvm-project/commit/c1b7460b5b705d983ac40ac37449911d132c7db4.diff

LOG: Revert "RegAlloc: do not consider liveins to EH-pad successors as liveout."

Some liveins *can* come from this block (e.g. any SSA value except the call),
it's only the ones that produce `landingpad` values that can't and I didn't
think it through properly.

Added: 
    

Modified: 
    llvm/lib/CodeGen/RegAllocFast.cpp
    llvm/test/CodeGen/X86/fast-isel-cmp-branch.ll

Removed: 
    llvm/test/CodeGen/X86/regalloc-tight-invoke.ll


################################################################################
diff  --git a/llvm/lib/CodeGen/RegAllocFast.cpp b/llvm/lib/CodeGen/RegAllocFast.cpp
index 994a1854a988..6d4194006afd 100644
--- a/llvm/lib/CodeGen/RegAllocFast.cpp
+++ b/llvm/lib/CodeGen/RegAllocFast.cpp
@@ -1002,7 +1002,7 @@ void RegAllocFast::setPhysReg(MachineInstr &MI, MachineOperand &MO,
 #ifndef NDEBUG
 
 void RegAllocFast::dumpState() const {
-  for (unsigned Unit = 0, UnitE = TRI->getNumRegUnits(); Unit != UnitE;
+  for (unsigned Unit = 1, UnitE = TRI->getNumRegUnits(); Unit != UnitE;
        ++Unit) {
     switch (unsigned VirtReg = RegUnitStates[Unit]) {
     case regFree:
@@ -1440,11 +1440,6 @@ void RegAllocFast::allocateBasicBlock(MachineBasicBlock &MBB) {
   assert(LiveVirtRegs.empty() && "Mapping not cleared from last block?");
 
   for (MachineBasicBlock *Succ : MBB.successors()) {
-    // EH-pads get their liveins from the runtime, not whatever happens in this
-    // block.
-    if (Succ->isEHPad())
-      continue;
-
     for (const MachineBasicBlock::RegisterMaskPair &LI : Succ->liveins())
       setPhysRegState(LI.PhysReg, regPreAssigned);
   }

diff  --git a/llvm/test/CodeGen/X86/fast-isel-cmp-branch.ll b/llvm/test/CodeGen/X86/fast-isel-cmp-branch.ll
index e262448468eb..9a54c8711f37 100644
--- a/llvm/test/CodeGen/X86/fast-isel-cmp-branch.ll
+++ b/llvm/test/CodeGen/X86/fast-isel-cmp-branch.ll
@@ -19,7 +19,7 @@ exit:
 ; 
diff erent basic block, so its operands aren't necessarily exported
 ; for cross-block usage.
 
-; CHECK: movb    %al, [[OFS:[0-9]*]](%rsp)
+; CHECK: movb    %cl, [[OFS:[0-9]*]](%rsp)
 ; CHECK: callq   {{_?}}bar
 ; CHECK: movb    [[OFS]](%rsp), %al
 

diff  --git a/llvm/test/CodeGen/X86/regalloc-tight-invoke.ll b/llvm/test/CodeGen/X86/regalloc-tight-invoke.ll
deleted file mode 100644
index 5367ffb67100..000000000000
--- a/llvm/test/CodeGen/X86/regalloc-tight-invoke.ll
+++ /dev/null
@@ -1,35 +0,0 @@
-; RUN: llc -O0 -mtriple=x86_64-apple-darwin %s -o - | FileCheck %s
-declare void @foo(i32, ...)
-
-declare i32 @__gxx_personality_v0(...)
-
-; We were running out of registers for this invoke, because:
-
-;     1. The lshr/and pattern gets matched to a no-REX MOV so that ah/bh/... can
-;        be used instead, cutting available registers for %b.arg down to eax, ebx,
-;        ecx, edx, esi, edi.
-;     2. We have a base pointer taking ebx out of contention.
-;     3. The landingpad block convinced us we should be defining rax here.
-;     3. The al fiddling for the varargs call only noted down that al was spillable,
-;        not ah or hax.
-;
-; So by the time we need to allocate a register for the call all registers are
-; tied up and unspillable.
-
-; CHECK-LABEL: bar:
-; CHECK: xorl %edi, %edi
-; CHECK: movb %dil, {{[0-9]+}}(%rbx)
-; CHECK: movb {{[0-9]+}}(%rbx), %al
-define i32 @bar(i32 %a, i32 %b, i32 %c, i32 %d, ...) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
-  %mem = alloca i32, i32 %a, align 32   ; Force rbx to be used as a base pointer
-  %b.tmp = lshr i32 %b, 8
-  %b.arg = and i32 %b.tmp, 255
-  invoke void(i32, ...) @foo(i32 42, i32* %mem, i32 %c, i32 %d, i32 %b.arg) to label %success unwind label %fail
-
-success:
-  ret i32 0
-fail:
-  %exc = landingpad { i8*, i32 } cleanup
-  %res = extractvalue { i8*, i32 } %exc, 1
-  ret i32 %res
-}