From 819207bec3b77be2d78f7ab21e44ac7b7b355cbf Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dim@FreeBSD.org>
Date: Thu, 3 Oct 2019 16:22:56 +0000
Subject: [PATCH] Merge r353031 from stable/12:

Pull in r357528 from upstream llvm trunk (by Craig Topper):

  [X86] Check MI.isConvertibleTo3Addr() before calling
  convertToThreeAddress in X86FixupLEAs.

  X86FixupLEAs just assumes convertToThreeAddress will return nullptr
  for any instruction that isn't convertible.

  But the code in convertToThreeAddress for X86 assumes that any
  instruction coming in has at least 2 operands and that the second one
  is a register. But those properties aren't guaranteed of all
  instructions. We should check the instruction property first.

Pull in r365720 from upstream llvm trunk (by Craig Topper):

  [X86] Don't convert 8 or 16 bit ADDs to LEAs on Atom in FixupLEAPass.

  We use the functions that convert to three address to do the
  conversion, but changing an 8 or 16 bit will cause it to create a
  virtual register. This can't be done after register allocation where
  this pass runs.

  I've switched the pass completely to a white list of instructions
  that can be converted to LEA instead of a blacklist that was
  incorrect. This will avoid surprises if we enhance the three address
  conversion function to include additional instructions in the future.

  Fixes PR42565.

This should fix assertions/segfaults when compiling certain ports with
CPUTYPE=atom.

Approved by:	re (kib)
PR:		240928
---
 contrib/llvm/lib/Target/X86/X86FixupLEAs.cpp | 33 +++++++++++++-------
 1 file changed, 21 insertions(+), 12 deletions(-)

diff --git a/contrib/llvm/lib/Target/X86/X86FixupLEAs.cpp b/contrib/llvm/lib/Target/X86/X86FixupLEAs.cpp
index a346085a52c..c45aeb198dd 100644
--- a/contrib/llvm/lib/Target/X86/X86FixupLEAs.cpp
+++ b/contrib/llvm/lib/Target/X86/X86FixupLEAs.cpp
@@ -154,6 +154,15 @@ FixupLEAPass::postRAConvertToLEA(MachineFunction::iterator &MFI,
     MFI->insert(MBBI, NewMI); // Insert the new inst
     return NewMI;
   }
+  }
+
+  if (!MI.isConvertibleTo3Addr())
+    return nullptr;
+
+  switch (MI.getOpcode()) {
+  default:
+    // Only convert instructions that we've verified are safe.
+    return nullptr;
   case X86::ADD64ri32:
   case X86::ADD64ri8:
   case X86::ADD64ri32_DB:
@@ -162,24 +171,24 @@ FixupLEAPass::postRAConvertToLEA(MachineFunction::iterator &MFI,
   case X86::ADD32ri8:
   case X86::ADD32ri_DB:
   case X86::ADD32ri8_DB:
-  case X86::ADD16ri:
-  case X86::ADD16ri8:
-  case X86::ADD16ri_DB:
-  case X86::ADD16ri8_DB:
     if (!MI.getOperand(2).isImm()) {
       // convertToThreeAddress will call getImm()
       // which requires isImm() to be true
       return nullptr;
     }
     break;
-  case X86::ADD16rr:
-  case X86::ADD16rr_DB:
-    if (MI.getOperand(1).getReg() != MI.getOperand(2).getReg()) {
-      // if src1 != src2, then convertToThreeAddress will
-      // need to create a Virtual register, which we cannot do
-      // after register allocation.
-      return nullptr;
-    }
+  case X86::SHL64ri:
+  case X86::SHL32ri:
+  case X86::INC64r:
+  case X86::INC32r:
+  case X86::DEC64r:
+  case X86::DEC32r:
+  case X86::ADD64rr:
+  case X86::ADD64rr_DB:
+  case X86::ADD32rr:
+  case X86::ADD32rr_DB:
+    // These instructions are all fine to convert.
+    break;
   }
   return TII->convertToThreeAddress(MFI, MI, nullptr);
 }
-- 
2.45.0