6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-10-25 10:27:04 +00:00
Code Issues Projects Releases Wiki Activity

If a conditional branch jumps to the same target, remove the condition

Browse Source 
Given that large parts of inst combine is restricted to instructions which have one use, getting rid of a use on the condition can help the effectiveness of the optimizer. Also, it allows the condition to potentially be deleted by instcombine rather than waiting for another pass.

I noticed this completely by accident in another test case. It's not anything that actually came from a real workload.

p.s. We should probably do the same thing for switch instructions.

Differential Revision: http://reviews.llvm.org/D8220



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231881 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Philip Reames
2015-03-10 22:52:37 +00:00
parent 107918efa2
commit fb4ffccacb
2 changed files with 25 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
test/Transforms/InstCombine/branch.ll Normal file
View File

@@ -0,0 +1,16 @@
; RUN: opt -instcombine -S < %s | FileCheck %s
define i32 @test(i32 %x) {
; CHECK-LABEL: @test
entry:
; CHECK-NOT: icmp
; CHECK: br i1 undef,
%cmp = icmp ult i32 %x, 7
br i1 %cmp, label %merge, label %merge
merge:
; CHECK-LABEL: merge:
; CHECK: ret i32 %x
ret i32 %x
}