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[flang] Disable noalias by default #142128

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Merged
merged 2 commits into from
May 30, 2025
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[flang] Disable noalias by default #142128

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645f6c3
[flang] Disable noalias captures(none) by default
tblah May 30, 2025
e956bfc
Re-enable captures(none)
tblah May 30, 2025
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15 changes: 12 additions & 3 deletions flang/lib/Optimizer/Passes/Pipelines.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,14 @@
/// common to flang and the test tools.

#include "flang/Optimizer/Passes/Pipelines.h"
#include "llvm/Support/CommandLine.h"

/// Force setting the no-alias attribute on fuction arguments when possible.
static llvm::cl::opt<bool> forceNoAlias("force-no-alias", llvm::cl::Hidden,
llvm::cl::init(false));
/// Force setting the no-capture attribute on fuction arguments when possible.
static llvm::cl::opt<bool> forceNoCapture("force-no-capture", llvm::cl::Hidden,
llvm::cl::init(false));

namespace fir {

Expand Down Expand Up @@ -350,9 +358,10 @@ void createDefaultFIRCodeGenPassPipeline(mlir::PassManager &pm,
else
framePointerKind = mlir::LLVM::framePointerKind::FramePointerKind::None;

bool setNoCapture = false, setNoAlias = false;
if (config.OptLevel.isOptimizingForSpeed())
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@vzakhari vzakhari May 30, 2025

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Tom, will you be okay if I just remove this if? The LIT tests should still work, and it will be easier to re-enable the code, when function speciailization is fixed.

setNoCapture = setNoAlias = true;
// TODO: re-enable setNoAlias by default (when optimizing for speed) once
// function specialization is fixed.
bool setNoAlias = forceNoAlias;
bool setNoCapture = forceNoCapture;
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@vzakhari vzakhari May 30, 2025

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Oh, I think this will revert more than I did. Nocapture was set before my change, but only for ref types (not for boxes).

Can you given me some time today to disable it correctly to resolve the exchange issue and avoid other regressions? Or is it crucial to resolve the exchange issue immediately? Please let me know.

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@tblah tblah May 30, 2025

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My bad I was rushing and missed this. It turns out to work fine with nocapture still enabled. I've updated the patch.


pm.addPass(fir::createFunctionAttr(
{framePointerKind, config.InstrumentFunctionEntry,
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2 changes: 1 addition & 1 deletion flang/test/Fir/polymorphic.fir
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@@ -1,4 +1,4 @@
// RUN: tco %s | FileCheck %s
// RUN: tco --force-no-capture %s | FileCheck %s

// Test code gen for unlimited polymorphic type descriptor.

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2 changes: 1 addition & 1 deletion flang/test/Fir/struct-passing-x86-64-byval.fir
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@@ -1,7 +1,7 @@
// Test X86-64 ABI rewrite of struct passed by value (BIND(C), VALUE derived types).
// This test test cases where the struct must be passed on the stack according
// to the System V ABI.
// RUN: tco --target=x86_64-unknown-linux-gnu %s | FileCheck %s
// RUN: tco --target=x86_64-unknown-linux-gnu --force-no-capture --force-no-alias %s | FileCheck %s

module attributes {fir.defaultkind = "a1c4d8i4l4r4", fir.kindmap = "", llvm.data_layout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128", llvm.target_triple = "x86_64-unknown-linux-gnu"} {

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2 changes: 1 addition & 1 deletion flang/test/Fir/target-rewrite-complex-10-x86.fir
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@@ -1,6 +1,6 @@
// Test COMPLEX(10) passing and returning on X86
// RUN: fir-opt --target-rewrite="target=x86_64-unknown-linux-gnu" %s | FileCheck %s --check-prefix=AMD64
// RUN: tco -target="x86_64-unknown-linux-gnu" %s | FileCheck %s --check-prefix=AMD64_LLVM
// RUN: tco -target="x86_64-unknown-linux-gnu" --force-no-alias --force-no-capture %s | FileCheck %s --check-prefix=AMD64_LLVM

module attributes {fir.defaultkind = "a1c4d8i4l4r4", fir.kindmap = "", llvm.data_layout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128", llvm.target_triple = "x86_64-unknown-linux-gnu"} {

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2 changes: 1 addition & 1 deletion flang/test/Fir/target.fir
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@@ -1,4 +1,4 @@
// RUN: tco --target=i386-unknown-linux-gnu %s | FileCheck %s --check-prefix=I32
// RUN: tco --target=i386-unknown-linux-gnu --force-no-alias --force-no-capture %s | FileCheck %s --check-prefix=I32
// RUN: tco --target=x86_64-unknown-linux-gnu %s | FileCheck %s --check-prefix=X64
// RUN: tco --target=aarch64-unknown-linux-gnu %s | FileCheck %s --check-prefix=AARCH64
// RUN: tco --target=powerpc64le-unknown-linux-gnu %s | FileCheck %s --check-prefix=PPC
Expand Down