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https://github.com/RPCS3/llvm-mirror.git
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a3044c7cda
This patch builds over https://reviews.llvm.org/rL303349 and replaces the use of the condition only if it is safe to do so. We should not blindly RAUW the condition if experimental.guard or assume is a use of that condition. This is because LVI may have used the guard/assume to identify the value of the condition, and RUAWing will fold the guard/assume and uses before the guards/assumes. Reviewers: sanjoy, reames, trentxintong, mkazantsev Reviewed by: sanjoy, reames Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D33257 llvm-svn: 303633
242 lines
6.2 KiB
LLVM
242 lines
6.2 KiB
LLVM
; RUN: opt -S -jump-threading -dce < %s | FileCheck %s
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-unknown-linux-gnu"
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; Function Attrs: nounwind uwtable
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define i32 @test1(i32 %a, i32 %b) #0 {
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entry:
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%cmp = icmp sgt i32 %a, 5
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tail call void @llvm.assume(i1 %cmp)
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%cmp1 = icmp sgt i32 %b, 1234
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br i1 %cmp1, label %if.then, label %if.else
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; CHECK-LABEL: @test1
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; CHECK: icmp sgt i32 %a, 5
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; CHECK: call void @llvm.assume
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; CHECK-NOT: icmp sgt i32 %a, 3
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; CHECK: ret i32
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if.then: ; preds = %entry
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%cmp2 = icmp sgt i32 %a, 3
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br i1 %cmp2, label %if.then3, label %return
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if.then3: ; preds = %if.then
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tail call void (...) @bar() #1
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br label %return
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if.else: ; preds = %entry
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tail call void (...) @car() #1
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br label %return
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return: ; preds = %if.else, %if.then, %if.then3
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%retval.0 = phi i32 [ 1, %if.then3 ], [ 0, %if.then ], [ 0, %if.else ]
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ret i32 %retval.0
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}
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define i32 @test2(i32 %a) #0 {
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entry:
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%cmp = icmp sgt i32 %a, 5
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tail call void @llvm.assume(i1 %cmp)
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%cmp1 = icmp sgt i32 %a, 3
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br i1 %cmp1, label %if.then, label %return
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; CHECK-LABEL: @test2
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; CHECK: icmp sgt i32 %a, 5
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; CHECK: tail call void @llvm.assume
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; CHECK: tail call void (...) @bar()
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; CHECK: ret i32 1
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if.then: ; preds = %entry
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tail call void (...) @bar() #1
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br label %return
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return: ; preds = %entry, %if.then
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%retval.0 = phi i32 [ 1, %if.then ], [ 0, %entry ]
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ret i32 %retval.0
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}
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@g = external global i32
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; Check that we do prove a fact using an assume within the block.
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; We can fold the assume based on the semantics of assume.
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define void @can_fold_assume(i32* %array) {
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; CHECK-LABEL: @can_fold_assume
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; CHECK-NOT: call void @llvm.assume
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; CHECK-NOT: br
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; CHECK: ret void
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%notnull = icmp ne i32* %array, null
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call void @llvm.assume(i1 %notnull)
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br i1 %notnull, label %normal, label %error
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normal:
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ret void
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error:
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store atomic i32 0, i32* @g unordered, align 4
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ret void
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}
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declare void @f(i1)
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declare void @exit()
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; We can fold the assume but not the uses before the assume.
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define void @cannot_fold_use_before_assume(i32* %array) {
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; CHECK-LABEL:@cannot_fold_use_before_assume
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; CHECK: @f(i1 %notnull)
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; CHECK-NEXT: exit()
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; CHECK-NOT: assume
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; CHECK-NEXT: ret void
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%notnull = icmp ne i32* %array, null
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call void @f(i1 %notnull)
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call void @exit()
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call void @llvm.assume(i1 %notnull)
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br i1 %notnull, label %normal, label %error
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normal:
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ret void
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error:
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store atomic i32 0, i32* @g unordered, align 4
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ret void
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}
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declare void @dummy(i1) nounwind argmemonly
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define void @can_fold_some_use_before_assume(i32* %array) {
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; CHECK-LABEL:@can_fold_some_use_before_assume
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; CHECK: @f(i1 %notnull)
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; CHECK-NEXT: @dummy(i1 true)
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; CHECK-NOT: assume
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; CHECK-NEXT: ret void
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%notnull = icmp ne i32* %array, null
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call void @f(i1 %notnull)
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call void @dummy(i1 %notnull)
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call void @llvm.assume(i1 %notnull)
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br i1 %notnull, label %normal, label %error
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normal:
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ret void
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error:
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store atomic i32 0, i32* @g unordered, align 4
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ret void
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}
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; FIXME: can fold assume and all uses before/after assume.
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; because the trapping exit call is after the assume.
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define void @can_fold_assume_and_all_uses(i32* %array) {
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; CHECK-LABEL:@can_fold_assume_and_all_uses
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; CHECK: @dummy(i1 %notnull)
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; CHECK-NEXT: assume(i1 %notnull)
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; CHECK-NEXT: exit()
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; CHECK-NEXT: %notnull2 = or i1 true, false
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; CHECK-NEXT: @f(i1 %notnull2)
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; CHECK-NEXT: ret void
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%notnull = icmp ne i32* %array, null
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call void @dummy(i1 %notnull)
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call void @llvm.assume(i1 %notnull)
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call void @exit()
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br i1 %notnull, label %normal, label %error
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normal:
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%notnull2 = or i1 %notnull, false
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call void @f(i1 %notnull2)
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ret void
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error:
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store atomic i32 0, i32* @g unordered, align 4
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ret void
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}
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declare void @fz(i8)
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; FIXME: We can fold assume to true, and the use after assume, but we do not do so
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; currently, because of the function call after the assume.
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define void @can_fold_assume2(i32* %array) {
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; CHECK-LABEL:@can_fold_assume2
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; CHECK: @f(i1 %notnull)
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; CHECK-NEXT: assume(i1 %notnull)
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; CHECK-NEXT: znotnull = zext i1 %notnull to i8
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; CHECK-NEXT: @f(i1 %notnull)
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; CHECK-NEXT: @f(i1 true)
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; CHECK-NEXT: @fz(i8 %znotnull)
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; CHECK-NEXT: ret void
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%notnull = icmp ne i32* %array, null
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call void @f(i1 %notnull)
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call void @llvm.assume(i1 %notnull)
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%znotnull = zext i1 %notnull to i8
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call void @f(i1 %notnull)
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br i1 %notnull, label %normal, label %error
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normal:
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call void @f(i1 %notnull)
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call void @fz(i8 %znotnull)
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ret void
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error:
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store atomic i32 0, i32* @g unordered, align 4
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ret void
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}
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declare void @llvm.experimental.guard(i1, ...)
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; FIXME: We can fold assume to true, but we do not do so
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; because of the guard following the assume.
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define void @can_fold_assume3(i32* %array){
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; CHECK-LABEL:@can_fold_assume3
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; CHECK: @f(i1 %notnull)
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; CHECK-NEXT: assume(i1 %notnull)
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; CHECK-NEXT: guard(i1 %notnull)
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; CHECK-NEXT: znotnull = zext i1 true to i8
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; CHECK-NEXT: @f(i1 true)
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; CHECK-NEXT: @fz(i8 %znotnull)
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; CHECK-NEXT: ret void
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%notnull = icmp ne i32* %array, null
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call void @f(i1 %notnull)
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call void @llvm.assume(i1 %notnull)
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call void(i1, ...) @llvm.experimental.guard(i1 %notnull) [ "deopt"() ]
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%znotnull = zext i1 %notnull to i8
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br i1 %notnull, label %normal, label %error
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normal:
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call void @f(i1 %notnull)
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call void @fz(i8 %znotnull)
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ret void
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error:
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store atomic i32 0, i32* @g unordered, align 4
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ret void
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}
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; can fold all uses and remove the cond
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define void @can_fold_assume4(i32* %array) {
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; CHECK-LABEL: can_fold_assume4
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; CHECK-NOT: notnull
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; CHECK: dummy(i1 true)
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; CHECK-NEXT: ret void
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%notnull = icmp ne i32* %array, null
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call void @exit()
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call void @dummy(i1 %notnull)
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call void @llvm.assume(i1 %notnull)
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br i1 %notnull, label %normal, label %error
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normal:
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ret void
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error:
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store atomic i32 0, i32* @g unordered, align 4
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ret void
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}
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; Function Attrs: nounwind
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declare void @llvm.assume(i1) #1
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declare void @bar(...)
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declare void @car(...)
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attributes #0 = { nounwind uwtable }
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attributes #1 = { nounwind }
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