Florian Hahn 13ffde316a
[ConstraintElim] Remove dead compares after simplification.
Remove compares after replacing all uses. Cleaning dead compares can
enable additional simplifications when adjusting the position of the
pass slightly. In particular, it seems like the additional dead
instructions may prevent SimplifyCFG performing some folds.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D158760
2023-08-24 22:12:57 +01:00

50 lines
1.5 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -passes=constraint-elimination -S %s | FileCheck %s
declare void @may_unwind()
declare i32 @__gxx_personality_v0(...)
define i1 @test_invoke_in_block_with_assume(i32 %x) personality ptr @__gxx_personality_v0 {
; CHECK-LABEL: @test_invoke_in_block_with_assume(
; CHECK-NEXT: entry:
; CHECK-NEXT: call void @may_unwind()
; CHECK-NEXT: [[C_1:%.*]] = icmp ult i32 [[X:%.*]], 10
; CHECK-NEXT: call void @llvm.assume(i1 [[C_1]])
; CHECK-NEXT: invoke void @may_unwind()
; CHECK-NEXT: to label [[CONT:%.*]] unwind label [[LPAD:%.*]]
; CHECK: cont:
; CHECK-NEXT: [[C_2:%.*]] = icmp ult i32 [[X]], 9
; CHECK-NEXT: [[RES_1:%.*]] = xor i1 true, [[C_2]]
; CHECK-NEXT: ret i1 [[RES_1]]
; CHECK: lpad:
; CHECK-NEXT: [[LP:%.*]] = landingpad { ptr, i32 }
; CHECK-NEXT: filter [0 x ptr] zeroinitializer
; CHECK-NEXT: [[C_3:%.*]] = icmp ult i32 [[X]], 9
; CHECK-NEXT: [[RES_2:%.*]] = xor i1 true, [[C_3]]
; CHECK-NEXT: ret i1 [[RES_2]]
;
entry:
call void @may_unwind()
%c.1 = icmp ult i32 %x, 10
call void @llvm.assume(i1 %c.1)
invoke void @may_unwind()
to label %cont unwind label %lpad
cont:
%t.1 = icmp ult i32 %x, 10
%c.2 = icmp ult i32 %x, 9
%res.1 = xor i1 %t.1, %c.2
ret i1 %res.1
lpad:
%lp = landingpad { ptr, i32 }
filter [0 x ptr] zeroinitializer
%t.2 = icmp ult i32 %x, 10
%c.3 = icmp ult i32 %x, 9
%res.2 = xor i1 %t.2, %c.3
ret i1 %res.2
}
declare void @llvm.assume(i1)