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|
; RUN: opt -passes='loop(simple-loop-unswitch),verify<loops>' -S < %s | FileCheck %s
; RUN: opt -verify-memoryssa -passes='loop-mssa(simple-loop-unswitch),verify<loops>' -S < %s | FileCheck %s
declare void @unknown()
declare void @unknown2()
@y = global i64 0, align 8
; The following is approximately:
; void f(bool *x) {
; for (int i = 0; i < 1; ++i) {
; if (*x) {
; if (y)
; unknown();
; else
; break;
; }
; }
; }
; 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_trivial(ptr %x) sanitize_memory {
; CHECK-LABEL: @may_not_execute_trivial(
entry:
%y = load i64, ptr @y, align 8
%y.cmp = icmp eq i64 %y, 0
br label %for.body
; CHECK: %[[Y:.*]] = load i64, ptr @y
; CHECK: %[[YCMP:.*]] = icmp eq i64 %[[Y]], 0
; CHECK-NOT: br i1
; CHECK: br label %for.body
for.body:
%i = phi i32 [ 0, %entry ], [ %inc, %for.inc ]
%x.load = load i1, ptr %x
br i1 %x.load, label %for.inc, label %if.then
; CHECK: %[[XLOAD:.*]] = load i1, ptr %x
; CHECK: br i1 %[[XLOAD]]
if.then:
br i1 %y.cmp, label %for.end, label %if.then4
; CHECK: br i1 %[[YCMP]]
if.then4:
call void @unknown()
br label %for.inc
for.inc:
%inc = add nsw i32 %i, 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_trivial(ptr %x, i1 %y) sanitize_memory {
; CHECK-LABEL: @may_not_execute2_trivial(
entry:
br label %for.body
; CHECK-NOT: br i1
; CHECK: br label %for.body
for.body:
%i = phi i32 [ 0, %entry ], [ %inc, %for.inc ]
%x.load = load i1, ptr %x
br i1 %x.load, label %for.inc, label %if.then
; CHECK: %[[XLOAD:.*]] = load i1, ptr %x
; CHECK: br i1 %[[XLOAD]]
if.then:
br i1 %y, label %for.end, label %if.then4
; CHECK: br i1 %y
if.then4:
call void @unknown()
br label %for.inc
for.inc:
%inc = add nsw i32 %i, 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() {
; for (int i = 0; i < 1; ++i) {
; if (y)
; unknown();
; else
; break;
; }
; }
; "if (y)" is guaranteed to execute; the loop can be unswitched.
define void @must_execute_trivial() sanitize_memory {
; CHECK-LABEL: @must_execute_trivial(
entry:
%y = load i64, ptr @y, align 8
%y.cmp = icmp eq i64 %y, 0
br label %for.body
; CHECK: %[[Y:.*]] = load i64, ptr @y
; CHECK: %[[YCMP:.*]] = icmp eq i64 %[[Y]], 0
; CHECK: br i1 %[[YCMP]], label %[[EXIT_SPLIT:.*]], label %[[PH:.*]]
;
; CHECK: [[PH]]:
; CHECK: br label %for.body
for.body:
%i = phi i32 [ 0, %entry ], [ %inc, %for.inc ]
br i1 %y.cmp, label %for.end, label %if.then4
; CHECK: br label %if.then4
if.then4:
call void @unknown()
br label %for.inc
for.inc:
%inc = add nsw i32 %i, 1
%cmp = icmp slt i32 %inc, 1
br i1 %cmp, label %for.body, label %for.end
for.end:
ret void
; CHECK: for.end:
; CHECK: br label %[[EXIT_SPLIT]]
;
; CHECK: [[EXIT_SPLIT]]:
; CHECK: ret void
}
|
