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https://github.com/RPCS3/llvm-mirror.git
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1542bebc55
Summary: Add a flag to the FunctionToLoopAdaptor that allows enabling MemorySSA only for the loop pass managers that are known to preserve it. If an LPM is known to have only loop transforms that *all* preserve MemorySSA, then use MemorySSA if `EnableMSSALoopDependency` is set. If an LPM has loop passes that do not preserve MemorySSA, then the flag passed is `false`, regardless of the value of `EnableMSSALoopDependency`. When using a custom loop pass pipeline via `passes=...`, use keyword `loop` vs `loop-mssa` to use MemorySSA in that LPM. If a loop that does not preserve MemorySSA is added while using the `loop-mssa` keyword, that's an error. Add the new `loop-mssa` keyword to a few tests where a difference occurs when enabling MemorySSA. Reviewers: chandlerc Subscribers: mehdi_amini, Prazek, george.burgess.iv, sanjoy.google, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D66376 llvm-svn: 369548
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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