This is an archive of the discontinued LLVM Phabricator instance.

Show First 20 Lines • Show All 2,904 Lines • ▼ Show 20 Lines	static bool unswitchLoop(Loop &L, DominatorTree &DT, LoopInfo &LI,
// a debugging.		// a debugging.
if (!NonTrivial && !EnableNonTrivialUnswitch)		if (!NonTrivial && !EnableNonTrivialUnswitch)
return false;		return false;

// Skip non-trivial unswitching for optsize functions.		// Skip non-trivial unswitching for optsize functions.
if (L.getHeader()->getParent()->hasOptSize())		if (L.getHeader()->getParent()->hasOptSize())
return false;		return false;

		// Skip non-trivial unswitching for loops that cannot be cloned.
		if (!L.isSafeToClone())
		return false;

// For non-trivial unswitching, because it often creates new loops, we rely on		// For non-trivial unswitching, because it often creates new loops, we rely on
// the pass manager to iterate on the loops rather than trying to immediately		// the pass manager to iterate on the loops rather than trying to immediately
// reach a fixed point. There is no substantial advantage to iterating		// reach a fixed point. There is no substantial advantage to iterating
// internally, and if any of the new loops are simplified enough to contain		// internally, and if any of the new loops are simplified enough to contain
// trivial unswitching we want to prefer those.		// trivial unswitching we want to prefer those.

// Try to unswitch the best invariant condition. We prefer this full unswitch to		// Try to unswitch the best invariant condition. We prefer this full unswitch to
// a partial unswitch when possible below the threshold.		// a partial unswitch when possible below the threshold.
▲ Show 20 Lines • Show All 155 Lines • Show Last 20 Lines

llvm/test/Transforms/SimpleLoopUnswitch/not-safe-to-clone.ll

This file was added.

				; RUN: opt -passes='unswitch<nontrivial>' %s -S \| FileCheck %s

				declare i1 @foo()

				; CHECK: define {{.*}} @mem_cgroup_node_nr_lru_pages
				define i32 @mem_cgroup_node_nr_lru_pages(i1 %tree) {
				entry:
				br label %for.cond

				for.cond: ; preds = %if.end8, %entry
				br i1 %tree, label %if.end8, label %if.else

				if.else: ; preds = %for.cond
				callbr void asm sideeffect ".pushsection __jump_table, \22aw\22 \0A\09.popsection \0A\09", "X,~{dirflag},~{fpsr},~{flags}"(i8* blockaddress(@mem_cgroup_node_nr_lru_pages, %for.cond5))
				to label %if.end8 [label %for.cond5]

				for.cond5: ; preds = %if.else, %for.cond5
				%call6 = call i1 @foo()
				br i1 %call6, label %if.end8.loopexit, label %for.cond5

				if.end8.loopexit: ; preds = %for.cond5
				br label %if.end8

				if.end8: ; preds = %if.end8.loopexit, %if.else, %for.cond
				br label %for.cond
				}

This is an archive of the discontinued LLVM Phabricator instance.

[SimpleLoopUnswitch] Don't non-trivially unswitch loops that are unsafe to cloneClosedPublic

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llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp

llvm/test/Transforms/SimpleLoopUnswitch/not-safe-to-clone.ll

[SimpleLoopUnswitch] Don't non-trivially unswitch loops that are unsafe to clone
ClosedPublic