6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-07-24 22:24:54 +00:00
Code Issues Projects Releases Wiki Activity

Fix updateTerminator to be resiliant to degenerate terminators where

Browse Source 
both fallthrough and a conditional branch target the same successor.
Gracefully delete the conditional branch and introduce any unconditional
branch needed to reach the actual successor. This fixes memory
corruption in 2009-06-15-RegScavengerAssert.ll and possibly other tests.

Also, while I'm here fix a latent bug I spotted by inspection. I never
applied the same fundamental fix to this fallthrough successor finding
logic that I did to the logic used when there are no conditional
branches. As a consequence it would have selected landing pads had they
be aligned in just the right way here. I don't have a test case as
I spotted this by inspection, and the previous time I found this
required have of TableGen's source code to produce it. =/ I hate backend
bugs. ;]

Thanks to Jim Grosbach for helping me reason through this and reviewing
the fix.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154867 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chandler Carruth
2012-04-16 22:03:00 +00:00
parent 68f89a6158
commit f1a60c734c
3 changed files with 31 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
test/CodeGen/X86/br-fold.ll
View File

@@ -1,7 +1,7 @@
; RUN: llc -march=x86-64 < %s | FileCheck %s
; CHECK: orq
; CHECK-NEXT: je
; CHECK-NEXT: .LBB0_1
@_ZN11xercesc_2_513SchemaSymbols21fgURI_SCHEMAFORSCHEMAE = external constant [33 x i16], align 32 ; <[33 x i16]*> [#uses=1]
@_ZN11xercesc_2_56XMLUni16fgNotationStringE = external constant [9 x i16], align 16 ; <[9 x i16]*> [#uses=1]