Improvements to demand analysis
d77501cd5b90
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Authored by simonpj on Dec 12 2018, 11:22 AM.

Description

Improvements to demand analysis

This patch collects a few improvements triggered by Trac Trac #15696,
and fixing Trac Trac #16029

Stop making toCleanDmd behave specially for unlifted types. This special case was the cause of stupid behaviour in Trac Trac #16029. And to my joy I discovered the let/app invariant rendered it unnecessary. (Maybe the special case pre-dated the let/app invariant.)

Result: less special-case handling in the compiler, and better perf for the compiled code.

In WwLib.mkWWstr_one, treat seqDmd like U(AAA). It was not being so treated before, which again led to stupid code.

There are .stderr test wibbles because we get slightly different
strictness signatures for an argumment of unlifted type:

<L,U> rather than <S,U>        for Int#
<S,U> rather than <S(S),U(U)>  for Int

Committed

simonpj

Dec 12 2018, 11:38 AM

Parents

rGHCded4a1db4d61: Typo fix, replace a foldl with foldl'

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				Path	Packages
	M			compiler/basicTypes/Demand.hs
	M			compiler/simplStg/StgLiftLams/Analysis.hs
	M			compiler/stranal/DmdAnal.hs
	M			compiler/stranal/WwLib.hs
	M			testsuite/tests/numeric/should_compile/T7116.stdout
	M			testsuite/tests/simplCore/should_compile/T13143.stderr
	M			testsuite/tests/simplCore/should_compile/T13543.stderr
	M			testsuite/tests/simplCore/should_compile/T3772.stdout
	M			testsuite/tests/simplCore/should_compile/T4930.stderr
	M			testsuite/tests/simplCore/should_compile/spec-inline.stderr
	M			testsuite/tests/stranal/should_compile/Makefile
	A			testsuite/tests/stranal/should_compile/T16029.hs
	A			testsuite/tests/stranal/should_compile/T16029.stdout
	M			testsuite/tests/stranal/should_compile/all.T
	M			testsuite/tests/stranal/sigs/HyperStrUse.stderr
	M			testsuite/tests/stranal/sigs/T12370.stderr
	M			testsuite/tests/stranal/sigs/T8598.stderr