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[InstCombine] Add the test that triggered the D60846 revert 

This is in preparation of D69571.
This commit is contained in:
Johannes Doerfert 2019-10-31 13:46:43 -05:00
parent 4de09e0f44
commit e15ab8f277
1 changed files with 42 additions and 0 deletions
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42
llvm/test/Transforms/InstCombine/known-non-zero.ll
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@ -91,3 +91,45 @@ exit:
%res = phi <8 x i64> [ %ctz, %non_zero ], [ zeroinitializer, %start ] %res = phi <8 x i64> [ %ctz, %non_zero ], [ zeroinitializer, %start ]
ret <8 x i64> %res ret <8 x i64> %res
} }
; Test that exposed a bug in the PHI handling after D60846. No folding should happen here!
define void @D60846_misompile(i1* %p) {
; CHECK-LABEL: @D60846_misompile(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[LOOP:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[I:%.*]] = phi i16 [ 0, [[ENTRY:%.*]] ], [ [[I_INC:%.*]], [[COMMON:%.*]] ]
; CHECK-NEXT: [[IS_ZERO:%.*]] = icmp eq i16 [[I]], 0
; CHECK-NEXT: br i1 [[IS_ZERO]], label [[COMMON]], label [[NON_ZERO:%.*]]
; CHECK: non_zero:
; CHECK-NEXT: [[IS_ONE:%.*]] = icmp eq i16 [[I]], 1
; CHECK-NEXT: store i1 [[IS_ONE]], i1* [[P:%.*]], align 1
; CHECK-NEXT: br label [[COMMON]]
; CHECK: common:
; CHECK-NEXT: [[I_INC]] = add i16 [[I]], 1
; CHECK-NEXT: [[LOOP_COND:%.*]] = icmp ult i16 [[I_INC]], 2
; CHECK-NEXT: br i1 [[LOOP_COND]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK: exit:
; CHECK-NEXT: ret void
;
entry:
br label %loop
loop: ; preds = %common, %entry
%i = phi i16 [ 0, %entry ], [ %i.inc, %common ]
%is_zero = icmp eq i16 %i, 0
br i1 %is_zero, label %common, label %non_zero
non_zero: ; preds = %loop
%is_one = icmp eq i16 %i, 1
store i1 %is_one, i1* %p
br label %common
common: ; preds = %non_zero, %loop
%i.inc = add i16 %i, 1
%loop_cond = icmp ult i16 %i.inc, 2
br i1 %loop_cond, label %loop, label %exit
exit: ; preds = %common
ret void
}