is_constant.ll
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; RUN: opt -jump-threading -S -verify < %s | FileCheck %s
; This is reduced from the Linux net/ipv4/tcp.c file built with ASAN. We
; don't want jump threading to split up a basic block which has a PHI node with
; at least one constant incoming value, whose value is used by an is.constant
; intrinsic with non-local uses. It could lead to later passes no DCE'ing
; invalid paths.
; CHECK-LABEL: define void @test1(
; CHECK-LABEL: bb_cond:
; CHECK-NOT: %sext = phi i64 [ %var, %entry ]
; CHECK-NEXT: %sext = phi i64 [ 24, %bb_constant ], [ %var, %entry ]
; CHECK-NEXT: %cond2 = icmp
; CHECK-NEXT: call i1 @llvm.is.constant.i64(
define void @test1(i32 %a, i64 %var) {
entry:
%cond1 = icmp ugt i32 %a, 24
br i1 %cond1, label %bb_constant, label %bb_cond
bb_constant:
br label %bb_cond
bb_cond:
%sext = phi i64 [ 24, %bb_constant ], [ %var, %entry ]
%cond2 = icmp ugt i64 %sext, 24
%is_constant = call i1 @llvm.is.constant.i64(i64 %sext)
br i1 %cond2, label %bb_then, label %bb_else
bb_then:
unreachable
bb_else:
unreachable
}
; Function Attrs: nounwind readnone willreturn
declare i1 @llvm.is.constant.i64(i64) #0
attributes #0 = { convergent nounwind readnone willreturn }