154 lines
3.7 KiB
LLVM
154 lines
3.7 KiB
LLVM
; RUN: opt < %s -loop-unswitch -verify-loop-info -S < %s 2>&1 | FileCheck %s
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@sink = global i32 0, align 4
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@y = global i64 0, align 8
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; The following is approximately:
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; void f(bool x, int p, int q) {
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; volatile bool x2 = x;
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; for (int i = 0; i < 1; ++i) {
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; if (x2) {
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; if (y)
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; sink = p;
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; else
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; sink = q;
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; }
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; }
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; }
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; With MemorySanitizer, the loop can not be unswitched on "y", because "y" could
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; be uninitialized when x == false.
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; Test that the branch on "y" is inside the loop (after the first unconditional
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; branch).
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define void @may_not_execute(i1 zeroext %x, i32 %p, i32 %q) sanitize_memory {
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; CHECK-LABEL: @may_not_execute(
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entry:
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; CHECK: %[[Y:.*]] = load i64, i64* @y, align 8
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; CHECK: %[[YB:.*]] = icmp eq i64 %[[Y]], 0
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; CHECK-NOT: br i1
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; CHECK: br label
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; CHECK: br i1 %[[YB]]
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%x2 = alloca i8, align 1
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%frombool1 = zext i1 %x to i8
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store volatile i8 %frombool1, i8* %x2, align 1
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%0 = load i64, i64* @y, align 8
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%tobool3 = icmp eq i64 %0, 0
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br label %for.body
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for.body:
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%i.01 = phi i32 [ 0, %entry ], [ %inc, %for.inc ]
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%x2.0. = load volatile i8, i8* %x2, align 1
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%tobool2 = icmp eq i8 %x2.0., 0
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br i1 %tobool2, label %for.inc, label %if.then
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if.then:
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br i1 %tobool3, label %if.else, label %if.then4
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if.then4:
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store volatile i32 %p, i32* @sink, align 4
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br label %for.inc
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if.else:
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store volatile i32 %q, i32* @sink, align 4
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br label %for.inc
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for.inc:
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%inc = add nsw i32 %i.01, 1
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%cmp = icmp slt i32 %inc, 1
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br i1 %cmp, label %for.body, label %for.end
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for.end:
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ret void
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}
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; The same as above, but "y" is a function parameter instead of a global.
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; This shows that it is not enough to suppress hoisting of load instructions,
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; the actual problem is in the speculative branching.
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define void @may_not_execute2(i1 zeroext %x, i1 zeroext %y, i32 %p, i32 %q) sanitize_memory {
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; CHECK-LABEL: @may_not_execute2(
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entry:
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; CHECK-NOT: br i1
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; CHECK: br label
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; CHECK: br i1 %y,
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%x2 = alloca i8, align 1
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%frombool2 = zext i1 %x to i8
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store volatile i8 %frombool2, i8* %x2, align 1
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br label %for.body
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for.body:
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%i.01 = phi i32 [ 0, %entry ], [ %inc, %for.inc ]
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%x2.0. = load volatile i8, i8* %x2, align 1
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%tobool3 = icmp eq i8 %x2.0., 0
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br i1 %tobool3, label %for.inc, label %if.then
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if.then:
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br i1 %y, label %if.then5, label %if.else
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if.then5:
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store volatile i32 %p, i32* @sink, align 4
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br label %for.inc
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if.else:
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store volatile i32 %q, i32* @sink, align 4
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br label %for.inc
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for.inc:
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%inc = add nsw i32 %i.01, 1
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%cmp = icmp slt i32 %inc, 1
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br i1 %cmp, label %for.body, label %for.end
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for.end:
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ret void
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}
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; The following is approximately:
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; void f(bool x, int p, int q) {
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; volatile bool x2 = x;
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; for (int i = 0; i < 1; ++i) {
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; if (y)
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; sink = p;
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; else
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; sink = q;
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; }
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; }
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; "if (y)" is guaranteed to execute; the loop can be unswitched.
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define void @must_execute(i1 zeroext %x, i32 %p, i32 %q) sanitize_memory {
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; CHECK-LABEL: @must_execute(
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entry:
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; CHECK: %[[Y:.*]] = load i64, i64* @y, align 8
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; CHECK-NEXT: %[[YB:.*]] = icmp eq i64 %[[Y]], 0
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; CHECK-NEXT: br i1 %[[YB]],
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%x2 = alloca i8, align 1
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%frombool1 = zext i1 %x to i8
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store volatile i8 %frombool1, i8* %x2, align 1
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%0 = load i64, i64* @y, align 8
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%tobool2 = icmp eq i64 %0, 0
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br label %for.body
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for.body:
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%i.01 = phi i32 [ 0, %entry ], [ %inc, %for.inc ]
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br i1 %tobool2, label %if.else, label %if.then
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if.then:
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store volatile i32 %p, i32* @sink, align 4
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br label %for.inc
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if.else:
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store volatile i32 %q, i32* @sink, align 4
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br label %for.inc
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for.inc:
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%inc = add nsw i32 %i.01, 1
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%cmp = icmp slt i32 %inc, 1
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br i1 %cmp, label %for.body, label %for.end
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for.end:
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ret void
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}
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