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llvm-mirror/test/Transforms/NewGVN/cyclic-phi-handling.ll
Daniel Berlin 764931b12c NewGVN: Fix PR 31501.
Summary: LLVM's non-standard notion of phi nodes means we can't both try to substitute for undef in phi nodes *and* use phi nodes as leaders all the time. This changes NewGVN to use the same semantics as SimplifyPHINode to decide which phi nodes are equivalent.

Reviewers: davide

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28312

llvm-svn: 291308
2017-01-07 00:01:42 +00:00

38 lines
1.3 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -basicaa -newgvn -S | FileCheck %s
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
define void @foo(i32 %arg, i32 %arg1, i32 (i32, i32)* %arg2) {
; CHECK-LABEL: @foo(
; CHECK-NEXT: bb:
; CHECK-NEXT: br label %bb3
; CHECK: bb3:
; CHECK-NEXT: [[TMP:%.*]] = phi i32 [ %arg1, %bb ], [ [[TMP:%.*]]4, %bb7 ]
; CHECK-NEXT: [[TMP4:%.*]] = phi i32 [ %arg, %bb ], [ [[TMP]], %bb7 ]
; CHECK-NEXT: [[TMP5:%.*]] = call i32 %arg2(i32 [[TMP4]], i32 [[TMP]])
; CHECK-NEXT: [[TMP6:%.*]] = icmp ne i32 [[TMP5]], 0
; CHECK-NEXT: br i1 [[TMP6]], label %bb7, label %bb8
; CHECK: bb7:
; CHECK-NEXT: br label %bb3
; CHECK: bb8:
; CHECK-NEXT: ret void
;
bb:
br label %bb3
;; While non-standard, llvm allows mutually dependent phi nodes
;; Ensure we do not infinite loop trying to process them
bb3: ; preds = %bb7, %bb
%tmp = phi i32 [ %arg1, %bb ], [ %tmp4, %bb7 ]
%tmp4 = phi i32 [ %arg, %bb ], [ %tmp, %bb7 ]
%tmp5 = call i32 %arg2(i32 %tmp4, i32 %tmp)
%tmp6 = icmp ne i32 %tmp5, 0
br i1 %tmp6, label %bb7, label %bb8
bb7: ; preds = %bb3
br label %bb3
bb8: ; preds = %bb3
ret void
}