[llvm] r331935 - [InstCombine] Widen guards with conditions between
Philip Reames via llvm-commits
llvm-commits at lists.llvm.org
Wed May 9 17:09:37 PDT 2018
Fixed. And thanks for the email btw.
Committed revision 331944.
On 05/09/2018 05:00 PM, Philip Reames via llvm-commits wrote:
>
> patch in progress, eta < 5 minutes
>
>
> On 05/09/2018 04:57 PM, Evgenii Stepanov wrote:
>> Breaks WERROR,
>> http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux/builds/11432/steps/bootstrap%20clang/logs/stdio
>>
>> On Wed, May 9, 2018 at 3:56 PM, Philip Reames via llvm-commits
>> <llvm-commits at lists.llvm.org <mailto:llvm-commits at lists.llvm.org>> wrote:
>>
>> Author: reames
>> Date: Wed May 9 15:56:32 2018
>> New Revision: 331935
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=331935&view=rev
>> <http://llvm.org/viewvc/llvm-project?rev=331935&view=rev>
>> Log:
>> [InstCombine] Widen guards with conditions between
>>
>> The previous handling for guard widening in InstCombine was
>> extremely restrictive. In particular, it didn't handle the common
>> case where we had two guards separated by a single icmp. Handle
>> this by scanning through a small fixed window of instructions to
>> find the next guard if needed.
>>
>> Differential Revision: https://reviews.llvm.org/D46203
>> <https://reviews.llvm.org/D46203>
>>
>>
>> Modified:
>> llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp
>> llvm/trunk/test/Transforms/InstCombine/call-guard.ll
>>
>> Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp?rev=331935&r1=331934&r2=331935&view=diff
>> <http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp?rev=331935&r1=331934&r2=331935&view=diff>
>> ==============================================================================
>> --- llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp
>> (original)
>> +++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp
>> Wed May 9 15:56:32 2018
>> @@ -79,6 +79,13 @@ static cl::opt<unsigned> UnfoldElementAt
>> cl::desc("Maximum number of elements in atomic memcpy the
>> optimizer is "
>> "allowed to unfold"));
>>
>> +static cl::opt<unsigned> GuardWideningWindow(
>> + "instcombine-guard-widening-window",
>> + cl::init(3),
>> + cl::desc("How wide an instruction window to bypass looking for "
>> + "another guard"));
>> +
>> +
>> /// Return the specified type promoted as it would be to pass
>> though a va_arg
>> /// area.
>> static Type *getPromotedType(Type *Ty) {
>> @@ -3624,8 +3631,16 @@ Instruction *InstCombiner::visitCallInst
>> }
>>
>> case Intrinsic::experimental_guard: {
>> - // Is this guard followed by another guard?
>> + // Is this guard followed by another guard? We scan forward
>> over a small
>> + // fixed window of instructions to handle common cases with
>> conditions
>> + // computed between guards.
>> Instruction *NextInst = II->getNextNode();
>> + for (int i = 0; i < GuardWideningWindow; i++) {
>> + // Note: Using context-free form to avoid compile time blow up
>> + if (!isSafeToSpeculativelyExecute(NextInst))
>> + break;
>> + NextInst = NextInst->getNextNode();
>> + }
>> Value *NextCond = nullptr;
>> if (match(NextInst,
>>
>> m_Intrinsic<Intrinsic::experimental_guard>(m_Value(NextCond)))) {
>> @@ -3636,6 +3651,12 @@ Instruction *InstCombiner::visitCallInst
>> return eraseInstFromFunction(*NextInst);
>>
>> // Otherwise canonicalize guard(a); guard(b) -> guard(a & b).
>> + Instruction* MoveI = II->getNextNode();
>> + while (MoveI != NextInst) {
>> + auto *Temp = MoveI;
>> + MoveI = MoveI->getNextNode();
>> + Temp->moveBefore(II);
>> + }
>> II->setArgOperand(0, Builder.CreateAnd(CurrCond, NextCond));
>> return eraseInstFromFunction(*NextInst);
>> }
>>
>> Modified: llvm/trunk/test/Transforms/InstCombine/call-guard.ll
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/call-guard.ll?rev=331935&r1=331934&r2=331935&view=diff
>> <http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/call-guard.ll?rev=331935&r1=331934&r2=331935&view=diff>
>> ==============================================================================
>> --- llvm/trunk/test/Transforms/InstCombine/call-guard.ll (original)
>> +++ llvm/trunk/test/Transforms/InstCombine/call-guard.ll Wed May
>> 9 15:56:32 2018
>> @@ -30,3 +30,81 @@ define void @test_guard_adjacent_diff_co
>> call void(i1, ...) @llvm.experimental.guard( i1 %C, i32 789 )[
>> "deopt"() ]
>> ret void
>> }
>> +
>> +; This version tests for the common form where the conditions are
>> +; between the guards
>> +define void @test_guard_adjacent_diff_cond2(i32 %V1, i32 %V2) {
>> +; CHECK-LABEL: @test_guard_adjacent_diff_cond2(
>> +; CHECK-NEXT: %1 = and i32 %V1, %V2
>> +; CHECK-NEXT: %2 = icmp slt i32 %1, 0
>> +; CHECK-NEXT: %and = and i32 %V1, 255
>> +; CHECK-NEXT: %C = icmp ult i32 %and, 129
>> +; CHECK-NEXT: %3 = and i1 %2, %C
>> +; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1
>> %3, i32 123) [ "deopt"() ]
>> +; CHECK-NEXT: ret void
>> + %A = icmp slt i32 %V1, 0
>> + call void(i1, ...) @llvm.experimental.guard( i1 %A, i32 123 )[
>> "deopt"() ]
>> + %B = icmp slt i32 %V2, 0
>> + call void(i1, ...) @llvm.experimental.guard( i1 %B, i32 456 )[
>> "deopt"() ]
>> + %and = and i32 %V1, 255
>> + %C = icmp sle i32 %and, 128
>> + call void(i1, ...) @llvm.experimental.guard( i1 %C, i32 789 )[
>> "deopt"() ]
>> + ret void
>> +}
>> +
>> +; Might not be legal to hoist the load above the first guard
>> since the
>> +; guard might control dereferenceability
>> +define void @negative_load(i32 %V1, i32* %P) {
>> +; CHECK-LABEL: @negative_load
>> +; CHECK: @llvm.experimental.guard
>> +; CHECK: @llvm.experimental.guard
>> + %A = icmp slt i32 %V1, 0
>> + call void(i1, ...) @llvm.experimental.guard( i1 %A, i32 123 )[
>> "deopt"() ]
>> + %V2 = load i32, i32* %P
>> + %B = icmp slt i32 %V2, 0
>> + call void(i1, ...) @llvm.experimental.guard( i1 %B, i32 456 )[
>> "deopt"() ]
>> + ret void
>> +}
>> +
>> +define void @deref_load(i32 %V1, i32* dereferenceable(4) %P) {
>> +; CHECK-LABEL: @deref_load
>> +; CHECK-NEXT: %V2 = load i32, i32* %P, align 4
>> +; CHECK-NEXT: %1 = and i32 %V2, %V1
>> +; CHECK-NEXT: %2 = icmp slt i32 %1, 0
>> +; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1
>> %2, i32 123) [ "deopt"() ]
>> + %A = icmp slt i32 %V1, 0
>> + call void(i1, ...) @llvm.experimental.guard( i1 %A, i32 123 )[
>> "deopt"() ]
>> + %V2 = load i32, i32* %P
>> + %B = icmp slt i32 %V2, 0
>> + call void(i1, ...) @llvm.experimental.guard( i1 %B, i32 456 )[
>> "deopt"() ]
>> + ret void
>> +}
>> +
>> +; The divide might fault above the guard
>> +define void @negative_div(i32 %V1, i32 %D) {
>> +; CHECK-LABEL: @negative_div
>> +; CHECK: @llvm.experimental.guard
>> +; CHECK: @llvm.experimental.guard
>> + %A = icmp slt i32 %V1, 0
>> + call void(i1, ...) @llvm.experimental.guard( i1 %A, i32 123 )[
>> "deopt"() ]
>> + %V2 = udiv i32 %V1, %D
>> + %B = icmp slt i32 %V2, 0
>> + call void(i1, ...) @llvm.experimental.guard( i1 %B, i32 456 )[
>> "deopt"() ]
>> + ret void
>> +}
>> +
>> +; Highlight the limit of the window in a case which would
>> otherwise be mergable
>> +define void @negative_window(i32 %V1, i32 %a, i32 %b, i32 %c,
>> i32 %d) {
>> +; CHECK-LABEL: @negative_window
>> +; CHECK: @llvm.experimental.guard
>> +; CHECK: @llvm.experimental.guard
>> + %A = icmp slt i32 %V1, 0
>> + call void(i1, ...) @llvm.experimental.guard( i1 %A, i32 123 )[
>> "deopt"() ]
>> + %V2 = add i32 %a, %b
>> + %V3 = add i32 %V2, %c
>> + %V4 = add i32 %V3, %d
>> + %B = icmp slt i32 %V4, 0
>> + call void(i1, ...) @llvm.experimental.guard( i1 %B, i32 456 )[
>> "deopt"() ]
>> + ret void
>> +}
>> +
>>
>>
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