From fc327a14c490db9d2e14c4c44ba8791dc54be02a Mon Sep 17 00:00:00 2001
From: Josh Bleecher Snyder <josharian@gmail.com>
Date: Tue, 4 Apr 2017 15:26:04 -0700
Subject: [PATCH] cmd/compile: remove order canonicalization rules from mips

CL 38801 introduced automatic commutative rule generation.
Manual order canonicalization rules thus lead to infinite loops.

Fixes #19842

Change-Id: I877c476152f4d207fdc67bc6f3018265aa9bc5ac
Reviewed-on: https://go-review.googlesource.com/39533
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
---
 src/cmd/compile/internal/ssa/gen/MIPS.rules |   3 -
 src/cmd/compile/internal/ssa/rewriteMIPS.go | 104 --------------------
 2 files changed, 107 deletions(-)

diff --git a/src/cmd/compile/internal/ssa/gen/MIPS.rules b/src/cmd/compile/internal/ssa/gen/MIPS.rules
index ec875ddea3..5124daa48d 100644
--- a/src/cmd/compile/internal/ssa/gen/MIPS.rules
+++ b/src/cmd/compile/internal/ssa/gen/MIPS.rules
@@ -611,9 +611,6 @@
 (SGTU x (MOVWconst [0])) -> (SGTUzero x)
 
 // mul with constant
-(Select1 (MULTU x (MOVWconst [c]))) && x.Op != OpMIPSMOVWconst -> (Select1 (MULTU (MOVWconst [c]) x ))
-(Select0 (MULTU x (MOVWconst [c]))) && x.Op != OpMIPSMOVWconst -> (Select0 (MULTU (MOVWconst [c]) x ))
-
 (Select1 (MULTU (MOVWconst [0]) _ )) -> (MOVWconst [0])
 (Select0 (MULTU (MOVWconst [0]) _ )) -> (MOVWconst [0])
 (Select1 (MULTU (MOVWconst [1]) x )) -> x
diff --git a/src/cmd/compile/internal/ssa/rewriteMIPS.go b/src/cmd/compile/internal/ssa/rewriteMIPS.go
index 082c67ad78..740b62a83f 100644
--- a/src/cmd/compile/internal/ssa/rewriteMIPS.go
+++ b/src/cmd/compile/internal/ssa/rewriteMIPS.go
@@ -7886,58 +7886,6 @@ func rewriteValueMIPS_OpSelect0(v *Value) bool {
 		v.AddArg(y)
 		return true
 	}
-	// match: (Select0 (MULTU x (MOVWconst [c])))
-	// cond: x.Op != OpMIPSMOVWconst
-	// result: (Select0 (MULTU (MOVWconst [c]) x ))
-	for {
-		v_0 := v.Args[0]
-		if v_0.Op != OpMIPSMULTU {
-			break
-		}
-		x := v_0.Args[0]
-		v_0_1 := v_0.Args[1]
-		if v_0_1.Op != OpMIPSMOVWconst {
-			break
-		}
-		c := v_0_1.AuxInt
-		if !(x.Op != OpMIPSMOVWconst) {
-			break
-		}
-		v.reset(OpSelect0)
-		v0 := b.NewValue0(v.Pos, OpMIPSMULTU, MakeTuple(types.UInt32, types.UInt32))
-		v1 := b.NewValue0(v.Pos, OpMIPSMOVWconst, types.UInt32)
-		v1.AuxInt = c
-		v0.AddArg(v1)
-		v0.AddArg(x)
-		v.AddArg(v0)
-		return true
-	}
-	// match: (Select0 (MULTU (MOVWconst [c]) x))
-	// cond: x.Op != OpMIPSMOVWconst
-	// result: (Select0 (MULTU (MOVWconst [c]) x ))
-	for {
-		v_0 := v.Args[0]
-		if v_0.Op != OpMIPSMULTU {
-			break
-		}
-		v_0_0 := v_0.Args[0]
-		if v_0_0.Op != OpMIPSMOVWconst {
-			break
-		}
-		c := v_0_0.AuxInt
-		x := v_0.Args[1]
-		if !(x.Op != OpMIPSMOVWconst) {
-			break
-		}
-		v.reset(OpSelect0)
-		v0 := b.NewValue0(v.Pos, OpMIPSMULTU, MakeTuple(types.UInt32, types.UInt32))
-		v1 := b.NewValue0(v.Pos, OpMIPSMOVWconst, types.UInt32)
-		v1.AuxInt = c
-		v0.AddArg(v1)
-		v0.AddArg(x)
-		v.AddArg(v0)
-		return true
-	}
 	// match: (Select0 (MULTU (MOVWconst [0]) _))
 	// cond:
 	// result: (MOVWconst [0])
@@ -8247,58 +8195,6 @@ func rewriteValueMIPS_OpSelect1(v *Value) bool {
 		v.AddArg(x)
 		return true
 	}
-	// match: (Select1 (MULTU x (MOVWconst [c])))
-	// cond: x.Op != OpMIPSMOVWconst
-	// result: (Select1 (MULTU (MOVWconst [c]) x ))
-	for {
-		v_0 := v.Args[0]
-		if v_0.Op != OpMIPSMULTU {
-			break
-		}
-		x := v_0.Args[0]
-		v_0_1 := v_0.Args[1]
-		if v_0_1.Op != OpMIPSMOVWconst {
-			break
-		}
-		c := v_0_1.AuxInt
-		if !(x.Op != OpMIPSMOVWconst) {
-			break
-		}
-		v.reset(OpSelect1)
-		v0 := b.NewValue0(v.Pos, OpMIPSMULTU, MakeTuple(types.UInt32, types.UInt32))
-		v1 := b.NewValue0(v.Pos, OpMIPSMOVWconst, types.UInt32)
-		v1.AuxInt = c
-		v0.AddArg(v1)
-		v0.AddArg(x)
-		v.AddArg(v0)
-		return true
-	}
-	// match: (Select1 (MULTU (MOVWconst [c]) x))
-	// cond: x.Op != OpMIPSMOVWconst
-	// result: (Select1 (MULTU (MOVWconst [c]) x ))
-	for {
-		v_0 := v.Args[0]
-		if v_0.Op != OpMIPSMULTU {
-			break
-		}
-		v_0_0 := v_0.Args[0]
-		if v_0_0.Op != OpMIPSMOVWconst {
-			break
-		}
-		c := v_0_0.AuxInt
-		x := v_0.Args[1]
-		if !(x.Op != OpMIPSMOVWconst) {
-			break
-		}
-		v.reset(OpSelect1)
-		v0 := b.NewValue0(v.Pos, OpMIPSMULTU, MakeTuple(types.UInt32, types.UInt32))
-		v1 := b.NewValue0(v.Pos, OpMIPSMOVWconst, types.UInt32)
-		v1.AuxInt = c
-		v0.AddArg(v1)
-		v0.AddArg(x)
-		v.AddArg(v0)
-		return true
-	}
 	// match: (Select1 (MULTU (MOVWconst [0]) _))
 	// cond:
 	// result: (MOVWconst [0])
-- 
2.48.1