From 47ea0e89486918fec7603aea838b83bc90853a2a Mon Sep 17 00:00:00 2001
From: Kai Nacke <kai@redstar.de>
Date: Sun, 18 Sep 2022 20:30:57 -0400
Subject: [m88k] Try to use a tree matcher in combiner.

llvm-tblgen crahes when using more than 2 instructions. :-(
---
 llvm/lib/Target/M88k/GISel/M88kPostLegalizerCombiner.cpp |  2 +-
 llvm/lib/Target/M88k/M88kCombine.td                      | 12 +++++++-----
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/llvm/lib/Target/M88k/GISel/M88kPostLegalizerCombiner.cpp b/llvm/lib/Target/M88k/GISel/M88kPostLegalizerCombiner.cpp
index adb63b19..a20659a 100644
--- a/llvm/lib/Target/M88k/GISel/M88kPostLegalizerCombiner.cpp
+++ b/llvm/lib/Target/M88k/GISel/M88kPostLegalizerCombiner.cpp
@@ -226,7 +226,7 @@ bool matchSubAddFromSubICmp(MachineInstr &MI, MachineRegisterInfo &MRI,
 // Match
 //  Unused, CarryBit = G_USUBU SrcB, SrcC
 //  Carry = G_ZEXT CarryBit
-//  Dst = G_UADD SrcA, Carry
+//  Dst = G_ADD SrcA, Carry
 // The returned MatchInfo transforms this sequence into
 //  Unused, Carry = G_USUBU SrcB, SrcC
 //  Dst, UnusedCarry = G_UADDE SrcA, Zero, Carry
diff --git a/llvm/lib/Target/M88k/M88kCombine.td b/llvm/lib/Target/M88k/M88kCombine.td
index c2d4456..d11e930 100644
--- a/llvm/lib/Target/M88k/M88kCombine.td
+++ b/llvm/lib/Target/M88k/M88kCombine.td
@@ -98,15 +98,17 @@ def subsub_from_subicmp : GICombineRule<
 //  Dst, UnusedCarry = G_USUBE SrcA, Zero, Carry
 // with SrcB' and SrcC' derived from SrcB and SrcC.
 def subadd_from_subicmp : GICombineRule<
-  (defs root:$root, build_fn_matchinfo:$matchinfo),
-  (match (wip_match_opcode G_SUB):$root,
-         [{ return matchSubAddFromSubICmp(*${root}, MRI, ${matchinfo}); }]),
-  (apply [{ Helper.applyBuildFn(*${root}, ${matchinfo}); }])>;
+  (defs root:$dst, build_fn_matchinfo:$matchinfo),
+  (match //(G_ICMP $icmp, $cc, $src2, $src3),
+         (G_ZEXT $zext, $icmp),
+         (G_SUB $dst, $src1, $zext):$submi,
+         [{ return matchSubAddFromSubICmp(*${submi}, MRI, ${matchinfo}); }]),
+  (apply [{ Helper.applyBuildFn(*${submi}, ${matchinfo}); }])>;
 
 // Combine
 //  Unused, CarryBit = G_USUBU SrcB, SrcC
 //  Carry = G_ZEXT CarryBit
-//  Dst = G_UADD SrcA, Carry
+//  Dst = G_ADD SrcA, Carry
 // into the instruction sequence
 //  Unused, Carry = G_USUBO SrcB, SrcC
 //  Dst, UnusedCarry = G_UADDE SrcA, Zero, Carry
-- 
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