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https://github.com/RPCS3/llvm-mirror.git
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55591e689c
This implements support for isKnownNonZero, computeKnownBits when freeze is involved. ``` br (x != 0), BB1, BB2 BB1: y = freeze x ``` In the above program, we can say that y is non-zero. The reason is as follows: (1) If x was poison, `br (x != 0)` raised UB (2) If x was fully undef, the branch again raised UB (3) If x was non-zero partially undef, say `undef | 1`, `freeze x` will return a nondeterministic value which is also non-zero. (4) If x was just a concrete value, it is trivial Reviewed By: nikic Differential Revision: https://reviews.llvm.org/D75808
169 lines
5.0 KiB
LLVM
169 lines
5.0 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -instsimplify -S | FileCheck %s
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define i64 @test0(i64 %x) {
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; CHECK-LABEL: @test0(
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; CHECK-NEXT: start:
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; CHECK-NEXT: [[A:%.*]] = icmp eq i64 [[X:%.*]], 0
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; CHECK-NEXT: br i1 [[A]], label [[EXIT:%.*]], label [[NON_ZERO:%.*]]
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; CHECK: non_zero:
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; CHECK-NEXT: br i1 false, label [[UNREACHABLE:%.*]], label [[EXIT]]
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; CHECK: unreachable:
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; CHECK-NEXT: br label [[EXIT]]
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; CHECK: exit:
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; CHECK-NEXT: [[C:%.*]] = phi i64 [ 0, [[START:%.*]] ], [ 1, [[NON_ZERO]] ], [ 2, [[UNREACHABLE]] ]
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; CHECK-NEXT: ret i64 [[C]]
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;
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start:
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%a = icmp eq i64 %x, 0
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br i1 %a, label %exit, label %non_zero
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non_zero:
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%b = icmp eq i64 %x, 0
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br i1 %b, label %unreachable, label %exit
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unreachable:
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br label %exit
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exit:
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%c = phi i64 [ 0, %start ], [ 1, %non_zero ], [ 2, %unreachable ]
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ret i64 %c
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}
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define i64 @test1(i64 %x) {
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; CHECK-LABEL: @test1(
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; CHECK-NEXT: start:
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; CHECK-NEXT: [[A:%.*]] = icmp eq i64 [[X:%.*]], 0
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; CHECK-NEXT: br i1 [[A]], label [[EXIT:%.*]], label [[NON_ZERO:%.*]]
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; CHECK: non_zero:
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; CHECK-NEXT: br i1 true, label [[EXIT]], label [[UNREACHABLE:%.*]]
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; CHECK: unreachable:
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; CHECK-NEXT: br label [[EXIT]]
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; CHECK: exit:
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; CHECK-NEXT: [[C:%.*]] = phi i64 [ 0, [[START:%.*]] ], [ [[X]], [[NON_ZERO]] ], [ 0, [[UNREACHABLE]] ]
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; CHECK-NEXT: ret i64 [[C]]
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;
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start:
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%a = icmp eq i64 %x, 0
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br i1 %a, label %exit, label %non_zero
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non_zero:
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%b = icmp ugt i64 %x, 0
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br i1 %b, label %exit, label %unreachable
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unreachable:
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br label %exit
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exit:
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%c = phi i64 [ 0, %start ], [ %x, %non_zero ], [ 0, %unreachable ]
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ret i64 %c
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}
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define i1 @test2(i64 %x, i1 %y) {
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; CHECK-LABEL: @test2(
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; CHECK-NEXT: start:
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; CHECK-NEXT: [[A:%.*]] = icmp eq i64 [[X:%.*]], 0
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; CHECK-NEXT: br i1 [[A]], label [[EXIT:%.*]], label [[NON_ZERO:%.*]]
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; CHECK: non_zero:
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; CHECK-NEXT: br i1 [[Y:%.*]], label [[ONE:%.*]], label [[TWO:%.*]]
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; CHECK: one:
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; CHECK-NEXT: br label [[MAINBLOCK:%.*]]
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; CHECK: two:
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; CHECK-NEXT: br label [[MAINBLOCK]]
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; CHECK: mainblock:
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; CHECK-NEXT: br label [[EXIT]]
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; CHECK: exit:
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; CHECK-NEXT: [[RES:%.*]] = phi i1 [ false, [[MAINBLOCK]] ], [ true, [[START:%.*]] ]
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; CHECK-NEXT: ret i1 [[RES]]
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;
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start:
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%a = icmp eq i64 %x, 0
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br i1 %a, label %exit, label %non_zero
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non_zero:
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br i1 %y, label %one, label %two
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one:
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br label %mainblock
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two:
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br label %mainblock
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mainblock:
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%p = phi i64 [ %x, %one ], [ 42, %two ]
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%cmp = icmp eq i64 %p, 0
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br label %exit
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exit:
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%res = phi i1 [ %cmp, %mainblock ], [ 1, %start ]
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ret i1 %res
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}
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; The code below exposed a bug similar to the one exposed by D60846, see the commit 6ea477590085.
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; In a nutshell, we should not replace %result.0 with 0 here.
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define zeroext i8 @update_phi_query_loc_in_recursive_call(i8* nocapture readonly %p){
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; CHECK-LABEL: @update_phi_query_loc_in_recursive_call(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br label [[FOR_COND:%.*]]
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; CHECK: for.cond:
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; CHECK-NEXT: [[RESULT_0:%.*]] = phi i8 [ 0, [[ENTRY:%.*]] ], [ [[CONV2:%.*]], [[FOR_BODY:%.*]] ]
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; CHECK-NEXT: [[SHIFT_0:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ 1, [[FOR_BODY]] ]
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; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[SHIFT_0]], 0
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; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[FOR_COND_CLEANUP:%.*]]
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; CHECK: for.cond.cleanup:
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; CHECK-NEXT: ret i8 [[RESULT_0]]
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; CHECK: for.body:
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; CHECK-NEXT: [[TMP0:%.*]] = load i8, i8* [[P:%.*]], align 1
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; CHECK-NEXT: [[CONV:%.*]] = zext i8 [[TMP0]] to i32
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; CHECK-NEXT: [[MUL:%.*]] = shl nuw nsw i32 [[SHIFT_0]], 3
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; CHECK-NEXT: [[SHL:%.*]] = shl nuw nsw i32 [[CONV]], [[MUL]]
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; CHECK-NEXT: [[TMP1:%.*]] = trunc i32 [[SHL]] to i8
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; CHECK-NEXT: [[CONV2]] = or i8 [[RESULT_0]], [[TMP1]]
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; CHECK-NEXT: br label [[FOR_COND]]
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;
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entry:
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br label %for.cond
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for.cond: ; preds = %for.body, %entry
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%result.0 = phi i8 [ 0, %entry ], [ %conv2, %for.body ]
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%shift.0 = phi i32 [ 0, %entry ], [ 1, %for.body ]
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%cmp = icmp eq i32 %shift.0, 0
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br i1 %cmp, label %for.body, label %for.cond.cleanup
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for.cond.cleanup: ; preds = %for.cond
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ret i8 %result.0
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for.body: ; preds = %for.cond
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%0 = load i8, i8* %p, align 1
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%conv = zext i8 %0 to i32
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%mul = shl nuw nsw i32 %shift.0, 3
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%shl = shl nuw nsw i32 %conv, %mul
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%1 = trunc i32 %shl to i8
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%conv2 = or i8 %result.0, %1
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%inc = add nuw nsw i32 %shift.0, 1
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br label %for.cond
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}
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define i1 @freeze_nonzero(i8 %x, i8 %mask) {
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; CHECK-LABEL: @freeze_nonzero(
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; CHECK-NEXT: [[Y:%.*]] = or i8 [[X:%.*]], [[MASK:%.*]]
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; CHECK-NEXT: [[C:%.*]] = icmp ne i8 [[Y]], 0
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; CHECK-NEXT: br i1 [[C]], label [[A:%.*]], label [[B:%.*]]
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; CHECK: A:
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; CHECK-NEXT: ret i1 false
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; CHECK: B:
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; CHECK-NEXT: ret i1 false
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;
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%y = or i8 %x, %mask
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%c = icmp ne i8 %y, 0
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br i1 %c, label %A, label %B
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A:
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%fr = freeze i8 %y
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%c2 = icmp eq i8 %fr, 0
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ret i1 %c2
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B:
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ret i1 0
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}
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