From: Josh Bleecher Snyder <josharian@gmail.com>
Date: Wed, 5 Aug 2015 23:43:49 +0000 (-0700)
Subject: [dev.ssa] cmd/compile: improve error message for phi location mismatch
X-Git-Tag: go1.7beta1~1623^2^2~303
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=5584523224dba203aab2e984ef6343db56bae249;p=gostls13.git

[dev.ssa] cmd/compile: improve error message for phi location mismatch

Change-Id: I402841743fcdc287631646039eb149f5cfdf886c
Reviewed-on: https://go-review.googlesource.com/13269
Reviewed-by: Keith Randall <khr@golang.org>
---

diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index 5c56b370bd..041e321717 100644
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -2111,8 +2111,8 @@ func genValue(v *ssa.Value) {
 		f := v.Block.Func
 		loc := f.RegAlloc[v.ID]
 		for _, a := range v.Args {
-			if f.RegAlloc[a.ID] != loc { // TODO: .Equal() instead?
-				v.Fatalf("phi arg at different location than phi %v %v %v %v", v, loc, a, f.RegAlloc[a.ID])
+			if aloc := f.RegAlloc[a.ID]; aloc != loc { // TODO: .Equal() instead?
+				v.Fatalf("phi arg at different location than phi: %v @ %v, but arg %v @ %v\n%s\n", v, loc, a, aloc, v.Block.Func)
 			}
 		}
 	case ssa.OpConst8, ssa.OpConst16, ssa.OpConst32, ssa.OpConst64, ssa.OpConstString, ssa.OpConstNil, ssa.OpConstBool: