llvm-6502/test/Transforms/SimplifyCFG/switch-to-icmp.ll
Hans Wennborg a121e24c54 simplifycfg: Fix integer overflow converting switch into icmp.
If a switch instruction has a case for every possible value of its type,
with the same successor, SimplifyCFG would replace it with an icmp ult,
but the computation of the bound overflows in that case, which inverts
the test.

Patch by Jed Davis!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179587 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-16 08:35:36 +00:00

58 lines
1016 B
LLVM

; RUN: opt -S -simplifycfg < %s | FileCheck %s
define zeroext i1 @test1(i32 %x) nounwind readnone ssp noredzone {
entry:
switch i32 %x, label %lor.rhs [
i32 2, label %lor.end
i32 1, label %lor.end
i32 3, label %lor.end
]
lor.rhs:
br label %lor.end
lor.end:
%0 = phi i1 [ true, %entry ], [ false, %lor.rhs ], [ true, %entry ], [ true, %entry ]
ret i1 %0
; CHECK: @test1
; CHECK: %x.off = add i32 %x, -1
; CHECK: %switch = icmp ult i32 %x.off, 3
}
define zeroext i1 @test2(i32 %x) nounwind readnone ssp noredzone {
entry:
switch i32 %x, label %lor.rhs [
i32 0, label %lor.end
i32 1, label %lor.end
]
lor.rhs:
br label %lor.end
lor.end:
%0 = phi i1 [ true, %entry ], [ false, %lor.rhs ], [ true, %entry ]
ret i1 %0
; CHECK: @test2
; CHECK: %switch = icmp ult i32 %x, 2
}
define i32 @test3(i1 %flag) {
entry:
switch i1 %flag, label %bad [
i1 true, label %good
i1 false, label %good
]
good:
ret i32 0
bad:
ret i32 1
; CHECK: @test3
; CHECK: entry:
; CHECK-NEXT: ret i32 0
}