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