[llvm] r315852 - [MergeFunctions] Replace all uses of unnamed_addr functions.

Wed Oct 18 21:48:17 PDT 2017

On 2017-10-18 18:45, Bob Wilson wrote:
> I tried the second patch (since you said it is more efficient). That
> fixes the problem. Can you get it committed soon?

r316145, and sorry for the trouble.

> 
>> On Oct 18, 2017, at 3:46 AM, whitequark <whitequark at whitequark.org>
>> wrote:
>> On 2017-10-17 23:53, Bob Wilson wrote:
>> 
>>> This change is causing an assertion failure for the Swift compiler
>>> 
>> 
> (https://ci.swift.org/view/swift-master-next/job/oss-swift-incremental-RA-osx-master-next/).
>>> Assertion failed: (isa<KeySansPointerT>(new_key) && "Invalid RAUW
>>> on
>>> key of ValueMap<>"), function allUsesReplacedWith, file
>>> 
>> 
> /Users/buildnode/jenkins/workspace/oss-swift-incremental-RA-osx-master-next/llvm/include/llvm/IR/ValueMap.h,
>>> line 275.
>>> The FunctionComparator utility used in MergeFunctions defines a
>>> GlobalNumberState that uses a ValueMap to map GlobalValues to
>>> integers. The ConstantExpr bitcast created here is not a
>>> GlobalValue.
>>> I investigated this and found that the assertion fails when the
>>> value
>>> is one of those new bitcast instructions. As an experiment, I
>>> changed
>>> the ValueMap in the FunctionComparator to operate on Values
>>> instead of
>>> GlobalValues and that fixed the assertion. I’m not sure that is
>>> the
>>> right solution, though.
>> 
>> I don't think this is the right solution. Could you please try one
>> of the attached patches? Either should work but the second is more
>> efficient.
>> 
>> Unfortunately, I don’t have a small testcase for this.
>> On Oct 15, 2017, at 5:29 AM, whitequark via llvm-commits
>> <llvm-commits at lists.llvm.org> wrote:
>> Author: whitequark
>> Date: Sun Oct 15 05:29:01 2017
>> New Revision: 315852
>> URL: http://llvm.org/viewvc/llvm-project?rev=315852&view=rev
>> Log:
>> [MergeFunctions] Replace all uses of unnamed_addr functions.
>> This reduces code size for constructs like vtables or interrupt
>> tables that refer to functions in global initializers.
>> Differential Revision: https://reviews.llvm.org/D34805
>> Added:
>> llvm/trunk/test/Transforms/MergeFunc/merge-unnamed-addr-bitcast.ll
>> llvm/trunk/test/Transforms/MergeFunc/merge-unnamed-addr.ll
>> Modified:
>> llvm/trunk/lib/Transforms/IPO/MergeFunctions.cpp
>> Modified: llvm/trunk/lib/Transforms/IPO/MergeFunctions.cpp
>> URL:
>> 
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/MergeFunctions.cpp?rev=315852&r1=315851&r2=315852&view=diff
>> 
> ==============================================================================
>> --- llvm/trunk/lib/Transforms/IPO/MergeFunctions.cpp (original)
>> +++ llvm/trunk/lib/Transforms/IPO/MergeFunctions.cpp Sun Oct 15
>> 05:29:01 2017
>> @@ -628,9 +628,15 @@ void MergeFunctions::filterInstsUnrelate
>> // call sites to point to F even when within the same translation
>> unit.
>> void MergeFunctions::writeThunk(Function *F, Function *G) {
>> if (!G->isInterposable() && !MergeFunctionsPDI) {
>> -    // Redirect direct callers of G to F. (See note on
>> MergeFunctionsPDI
>> -    // above).
>> -    replaceDirectCallers(G, F);
>> +    if (G->hasGlobalUnnamedAddr()) {
>> +      // If G's address is not significant, replace it entirely.
>> +      Constant *BitcastF = ConstantExpr::getBitCast(F,
>> G->getType());
>> +      G->replaceAllUsesWith(BitcastF);
>> +    } else {
>> +      // Redirect direct callers of G to F. (See note on
>> MergeFunctionsPDI
>> +      // above).
>> +      replaceDirectCallers(G, F);
>> +    }
>> }
>> // If G was internal then we may have replaced all uses of G with
>> F. If so,
>> Added:
>> llvm/trunk/test/Transforms/MergeFunc/merge-unnamed-addr-bitcast.ll
>> URL:
>> 
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/MergeFunc/merge-unnamed-addr-bitcast.ll?rev=315852&view=auto
>> 
> ==============================================================================
>> ---
>> llvm/trunk/test/Transforms/MergeFunc/merge-unnamed-addr-bitcast.ll
>> (added)
>> +++
>> llvm/trunk/test/Transforms/MergeFunc/merge-unnamed-addr-bitcast.ll
>> Sun Oct 15 05:29:01 2017
>> @@ -0,0 +1,30 @@
>> +; RUN: opt -S -mergefunc < %s | FileCheck %s
>> +
>> +%A = type { i32 }
>> +%B = type { i32 }
>> +
>> +; CHECK-NOT: @b
>> +
>> + at x = constant { i32 (i32)*, i32 (i32)* }
>> +  { i32 (i32)* bitcast (i32 (%A)* @a to i32 (i32)*),
>> +    i32 (i32)* bitcast (i32 (%B)* @b to i32 (i32)*) }
>> +; CHECK: { i32 (i32)* bitcast (i32 (%A)* @a to i32 (i32)*), i32
>> (i32)* bitcast (i32 (%A)* @a to i32 (i32)*) }
>> +
>> +define internal i32 @a(%A) unnamed_addr {
>> +  extractvalue %A %0, 0
>> +  xor i32 %2, 0
>> +  ret i32 %3
>> +}
>> +
>> +define internal i32 @b(%B) unnamed_addr {
>> +  extractvalue %B %0, 0
>> +  xor i32 %2, 0
>> +  ret i32 %3
>> +}
>> +
>> +define i32 @c(i32) {
>> +  insertvalue %B undef, i32 %0, 0
>> +  call i32 @b(%B %2)
>> +; CHECK: call i32 bitcast (i32 (%A)* @a to i32 (%B)*)(%B %2)
>> +  ret i32 %3
>> +}
>> Added: llvm/trunk/test/Transforms/MergeFunc/merge-unnamed-addr.ll
>> URL:
>> 
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/MergeFunc/merge-unnamed-addr.ll?rev=315852&view=auto
>> 
> ==============================================================================
>> --- llvm/trunk/test/Transforms/MergeFunc/merge-unnamed-addr.ll
>> (added)
>> +++ llvm/trunk/test/Transforms/MergeFunc/merge-unnamed-addr.ll Sun
>> Oct 15 05:29:01 2017
>> @@ -0,0 +1,18 @@
>> +; RUN: opt -S -mergefunc < %s | FileCheck %s
>> +
>> +; CHECK-NOT: @b
>> +
>> + at x = constant { i32 (i32)*, i32 (i32)* } { i32 (i32)* @a, i32
>> (i32)* @b }
>> +; CHECK: { i32 (i32)* @a, i32 (i32)* @a }
>> +
>> +define internal i32 @a(i32 %a) unnamed_addr {
>> +  %b = xor i32 %a, 0
>> +  %c = xor i32 %b, 0
>> +  ret i32 %c
>> +}
>> +
>> +define internal i32 @b(i32 %a) unnamed_addr {
>> +  %b = xor i32 %a, 0
>> +  %c = xor i32 %b, 0
>> +  ret i32 %c
>> +}
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> 
> --
> whitequark<fix-mergefunc-2.patch><fix-mergefunc-1.patch>

-- 
whitequark