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llvm/test/Transforms/SCCP/switch.ll

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; CHECK-NEXT: ret void ; CHECK-NEXT: ret void
; ;
switch i32 undef, label %d [] switch i32 undef, label %d []
d: d:
call void @foo() call void @foo()
ret void ret void
} }
define i32 @test_duplicate_successors_phi(i1 %c, i32 %x) { define i32 @test_duplicate_successors_phi(i1 %c, i32 %x) {
nikicAuthorUnsubmitted
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This test change shows another weakness of the previous approach: Even though we already determined that here only the default edge is feasible, we did not make use of this fact, because the target block is still reachable through a different edge. Because ConstantFoldTerminator was called for the predecessors of unreachable blocks, this case was missed.

nikic: This test change shows another weakness of the previous approach: Even though we already…
; CHECK-LABEL: @test_duplicate_successors_phi( ; CHECK-LABEL: @test_duplicate_successors_phi(
; CHECK-NEXT: entry: ; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[C:%.*]], label [[SWITCH:%.*]], label [[END:%.*]] ; CHECK-NEXT: br i1 [[C:%.*]], label [[SWITCH:%.*]], label [[END:%.*]]
; CHECK: switch: ; CHECK: switch:
; CHECK-NEXT: switch i32 -1, label [[SWITCH_DEFAULT:%.*]] [ ; CHECK-NEXT: br label [[SWITCH_DEFAULT:%.*]]
; CHECK-NEXT: i32 0, label [[END]]
; CHECK-NEXT: i32 1, label [[END]]
; CHECK-NEXT: ]
; CHECK: switch.default: ; CHECK: switch.default:
; CHECK-NEXT: ret i32 -1 ; CHECK-NEXT: ret i32 -1
; CHECK: end: ; CHECK: end:
; CHECK-NEXT: [[PHI:%.*]] = phi i32 [ [[X:%.*]], [[ENTRY:%.*]] ], [ 1, [[SWITCH]] ], [ 1, [[SWITCH]] ] ; CHECK-NEXT: ret i32 [[X:%.*]]
; CHECK-NEXT: ret i32 [[PHI]]
; ;
entry: entry:
br i1 %c, label %switch, label %end br i1 %c, label %switch, label %end
switch: switch:
switch i32 -1, label %switch.default [ switch i32 -1, label %switch.default [
i32 0, label %end i32 0, label %end
i32 1, label %end i32 1, label %end
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