llvm/test/Transforms/SimplifyCFG/switch-on-const-select.ll
Dan Gohman 3b205175ea Fix SpeculativelyExecuteBB to either speculate all or none of the phis
present in the bottom of the CFG triangle, as the transformation isn't
ever valuable if the branch can't be eliminated.

Also, unify some heuristics between SimplifyCFG's multiple
if-converters, for consistency.

This fixes rdar://10627242.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147630 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-05 23:58:56 +00:00

139 lines
3.2 KiB
LLVM

; RUN: opt < %s -simplifycfg -S | FileCheck %s
; Test basic folding to a conditional branch.
define i32 @foo(i64 %x, i64 %y) nounwind {
; CHECK: @foo
entry:
%eq = icmp eq i64 %x, %y
br i1 %eq, label %b, label %switch
switch:
%lt = icmp slt i64 %x, %y
; CHECK: br i1 %lt, label %a, label %b
%qux = select i1 %lt, i32 0, i32 2
switch i32 %qux, label %bees [
i32 0, label %a
i32 1, label %b
i32 2, label %b
]
a:
tail call void @bees.a() nounwind
ret i32 1
; CHECK: b:
; CHECK-NEXT: %retval = phi i32 [ 0, %switch ], [ 2, %entry ]
b:
%retval = phi i32 [0, %switch], [0, %switch], [2, %entry]
tail call void @bees.b() nounwind
ret i32 %retval
; CHECK-NOT: bees:
bees:
tail call void @llvm.trap() nounwind
unreachable
}
; Test basic folding to an unconditional branch.
define i32 @bar(i64 %x, i64 %y) nounwind {
; CHECK: @bar
entry:
; CHECK-NEXT: entry:
; CHECK-NEXT: tail call void @bees.a() nounwind
; CHECK-NEXT: ret i32 0
%lt = icmp slt i64 %x, %y
%qux = select i1 %lt, i32 0, i32 2
switch i32 %qux, label %bees [
i32 0, label %a
i32 1, label %b
i32 2, label %a
]
a:
%retval = phi i32 [0, %entry], [0, %entry], [1, %b]
tail call void @bees.a() nounwind
ret i32 0
b:
tail call void @bees.b() nounwind
br label %a
bees:
tail call void @llvm.trap() nounwind
unreachable
}
; Test the edge case where both values from the select are the default case.
define void @bazz(i64 %x, i64 %y) nounwind {
; CHECK: @bazz
entry:
; CHECK-NEXT: entry:
; CHECK-NEXT: tail call void @bees.b() nounwind
; CHECK-NEXT: ret void
%lt = icmp slt i64 %x, %y
%qux = select i1 %lt, i32 10, i32 12
switch i32 %qux, label %b [
i32 0, label %a
i32 1, label %bees
i32 2, label %bees
]
a:
tail call void @bees.a() nounwind
ret void
b:
tail call void @bees.b() nounwind
ret void
bees:
tail call void @llvm.trap()
unreachable
}
; Test the edge case where both values from the select are equal.
define void @quux(i64 %x, i64 %y) nounwind {
; CHECK: @quux
entry:
; CHECK-NEXT: entry:
; CHECK-NEXT: tail call void @bees.a() nounwind
; CHECK-NEXT: ret void
%lt = icmp slt i64 %x, %y
%qux = select i1 %lt, i32 0, i32 0
switch i32 %qux, label %b [
i32 0, label %a
i32 1, label %bees
i32 2, label %bees
]
a:
tail call void @bees.a() nounwind
ret void
b:
tail call void @bees.b() nounwind
ret void
bees:
tail call void @llvm.trap()
unreachable
}
; A final test, for phi node munging.
define i32 @xyzzy(i64 %x, i64 %y) {
; CHECK: @xyzzy
entry:
%eq = icmp eq i64 %x, %y
br i1 %eq, label %r, label %cont
cont:
; CHECK: %lt = icmp slt i64 %x, %y
%lt = icmp slt i64 %x, %y
; CHECK-NEXT: select i1 %lt, i32 -1, i32 1
%qux = select i1 %lt, i32 0, i32 2
switch i32 %qux, label %bees [
i32 0, label %a
i32 1, label %r
i32 2, label %r
]
r:
%val = phi i32 [0, %entry], [1, %cont], [1, %cont]
ret i32 %val
a:
ret i32 -1
; CHECK-NOT: bees:
bees:
tail call void @llvm.trap()
unreachable
}
declare void @llvm.trap() nounwind noreturn
declare void @bees.a() nounwind
declare void @bees.b() nounwind