143 lines
3.3 KiB
LLVM
143 lines
3.3 KiB
LLVM
; RUN: opt -passes='loop(unswitch),verify<loops>' -S < %s | FileCheck %s
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; RUN: opt -verify-memoryssa -passes='loop-mssa(unswitch),verify<loops>' -S < %s | FileCheck %s
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declare void @unknown()
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declare void @unknown2()
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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) {
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; for (int i = 0; i < 1; ++i) {
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; if (*x) {
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; if (y)
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; unknown();
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; else
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; break;
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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_trivial(i1* %x) sanitize_memory {
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; CHECK-LABEL: @may_not_execute_trivial(
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entry:
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%y = load i64, i64* @y, align 8
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%y.cmp = icmp eq i64 %y, 0
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br label %for.body
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; CHECK: %[[Y:.*]] = load i64, i64* @y
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; CHECK: %[[YCMP:.*]] = icmp eq i64 %[[Y]], 0
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; CHECK-NOT: br i1
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; CHECK: br label %for.body
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for.body:
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%i = phi i32 [ 0, %entry ], [ %inc, %for.inc ]
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%x.load = load i1, i1* %x
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br i1 %x.load, label %for.inc, label %if.then
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; CHECK: %[[XLOAD:.*]] = load i1, i1* %x
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; CHECK: br i1 %[[XLOAD]]
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if.then:
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br i1 %y.cmp, label %for.end, label %if.then4
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; CHECK: br i1 %[[YCMP]]
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if.then4:
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call void @unknown()
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br label %for.inc
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for.inc:
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%inc = add nsw i32 %i, 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_trivial(i1* %x, i1 %y) sanitize_memory {
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; CHECK-LABEL: @may_not_execute2_trivial(
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entry:
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br label %for.body
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; CHECK-NOT: br i1
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; CHECK: br label %for.body
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for.body:
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%i = phi i32 [ 0, %entry ], [ %inc, %for.inc ]
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%x.load = load i1, i1* %x
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br i1 %x.load, label %for.inc, label %if.then
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; CHECK: %[[XLOAD:.*]] = load i1, i1* %x
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; CHECK: br i1 %[[XLOAD]]
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if.then:
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br i1 %y, label %for.end, label %if.then4
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; CHECK: br i1 %y
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if.then4:
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call void @unknown()
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br label %for.inc
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for.inc:
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%inc = add nsw i32 %i, 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() {
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; for (int i = 0; i < 1; ++i) {
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; if (y)
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; unknown();
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; else
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; break;
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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_trivial() sanitize_memory {
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; CHECK-LABEL: @must_execute_trivial(
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entry:
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%y = load i64, i64* @y, align 8
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%y.cmp = icmp eq i64 %y, 0
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br label %for.body
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; CHECK: %[[Y:.*]] = load i64, i64* @y
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; CHECK: %[[YCMP:.*]] = icmp eq i64 %[[Y]], 0
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; CHECK: br i1 %[[YCMP]], label %[[EXIT_SPLIT:.*]], label %[[PH:.*]]
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;
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; CHECK: [[PH]]:
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; CHECK: br label %for.body
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for.body:
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%i = phi i32 [ 0, %entry ], [ %inc, %for.inc ]
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br i1 %y.cmp, label %for.end, label %if.then4
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; CHECK: br label %if.then4
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if.then4:
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call void @unknown()
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br label %for.inc
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for.inc:
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%inc = add nsw i32 %i, 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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; CHECK: for.end:
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; CHECK: br label %[[EXIT_SPLIT]]
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;
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; CHECK: [[EXIT_SPLIT]]:
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; CHECK: ret void
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}
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