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9e24ab7252
This patch adds a pass for doing PowerPC peephole optimizations at the MI level while the code is still in SSA form. This allows for easy modifications to the instructions while depending on a subsequent pass of DCE. Both passes are very fast due to the characteristics of SSA. At this time, the only peepholes added are for cleaning up various redundancies involving the XXPERMDI instruction. However, I would expect this will be a useful place to add more peepholes for inefficiencies generated during instruction selection. The pass is placed after VSX swap optimization, as it is best to let that pass remove unnecessary swaps before performing any remaining clean-ups. The utility of these clean-ups are demonstrated by changes to four existing test cases, all of which now have tighter expected code generation. I've also added Eric Schweiz's bugpoint-reduced test from PR25157, for which we now generate tight code. One other test started failing for me, and I've fixed it (test/Transforms/PlaceSafepoints/finite-loops.ll) as well; this is not related to my changes, and I'm not sure why it works before and not after. The problem is that the CHECK-NOT: of "statepoint" from test1 fails because of the "statepoint" in test2, and so forth. Adding a CHECK-LABEL in between keeps the different occurrences of that string properly scoped. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252651 91177308-0d34-0410-b5e6-96231b3b80d8
143 lines
3.2 KiB
LLVM
143 lines
3.2 KiB
LLVM
; Tests to ensure that we are not placing backedge safepoints in
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; loops which are clearly finite.
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;; RUN: opt %s -place-safepoints -spp-counted-loop-trip-width=32 -S | FileCheck %s
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;; RUN: opt %s -place-safepoints -spp-counted-loop-trip-width=64 -S | FileCheck %s -check-prefix=COUNTED-64
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; A simple counted loop with trivially known range
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define void @test1(i32) gc "statepoint-example" {
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; CHECK-LABEL: test1
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; CHECK-LABEL: entry
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; CHECK: statepoint
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; CHECK-LABEL: loop
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; CHECK-NOT: statepoint
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; CHECK-LABEL: exit
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entry:
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br label %loop
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loop:
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%counter = phi i32 [ 0 , %entry ], [ %counter.inc , %loop ]
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%counter.inc = add i32 %counter, 1
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%counter.cmp = icmp slt i32 %counter.inc, 16
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br i1 %counter.cmp, label %loop, label %exit
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exit:
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ret void
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}
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; The same counted loop, but with an unknown early exit
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define void @test2(i32) gc "statepoint-example" {
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; CHECK-LABEL: test2
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; CHECK-LABEL: entry
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; CHECK: statepoint
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; CHECK-LABEL: loop
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; CHECK-NOT: statepoint
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; CHECK-LABEL: exit
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entry:
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br label %loop
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loop:
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%counter = phi i32 [ 0 , %entry ], [ %counter.inc , %continue ]
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%counter.inc = add i32 %counter, 1
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%counter.cmp = icmp slt i32 %counter.inc, 16
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br i1 undef, label %continue, label %exit
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continue:
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br i1 %counter.cmp, label %loop, label %exit
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exit:
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ret void
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}
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; The range is a 8 bit value and we can't overflow
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define void @test3(i8 %upper) gc "statepoint-example" {
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; CHECK-LABEL: test3
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; CHECK-LABEL: entry
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; CHECK: statepoint
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; CHECK-LABEL: loop
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; CHECK-NOT: statepoint
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; CHECK-LABEL: exit
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entry:
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br label %loop
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loop:
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%counter = phi i8 [ 0 , %entry ], [ %counter.inc , %loop ]
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%counter.inc = add nsw i8 %counter, 1
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%counter.cmp = icmp slt i8 %counter.inc, %upper
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br i1 %counter.cmp, label %loop, label %exit
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exit:
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ret void
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}
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; The range is a 64 bit value
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define void @test4(i64 %upper) gc "statepoint-example" {
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; CHECK-LABEL: test4
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; CHECK-LABEL: entry
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; CHECK: statepoint
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; CHECK-LABEL: loop
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; CHECK: statepoint
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; CHECK-LABEL: exit
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; COUNTED-64-LABEL: test4
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; COUNTED-64-LABEL: entry
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; COUNTED-64: statepoint
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; COUNTED-64-LABEL: loop
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; COUNTED-64-NOT: statepoint
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; COUNTED-64-LABEL: exit
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entry:
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br label %loop
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loop:
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%counter = phi i64 [ 0 , %entry ], [ %counter.inc , %loop ]
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%counter.inc = add i64 %counter, 1
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%counter.cmp = icmp slt i64 %counter.inc, %upper
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br i1 %counter.cmp, label %loop, label %exit
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exit:
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ret void
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}
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; This loop can run infinitely (for %upper == INT64_MAX) so it needs a
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; safepoint.
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define void @test5(i64 %upper) gc "statepoint-example" {
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; CHECK-LABEL: test5
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; CHECK-LABEL: entry
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; CHECK: statepoint
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; CHECK-LABEL: loop
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; CHECK: statepoint
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; CHECK-LABEL: exit
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; COUNTED-64-LABEL: test5
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; COUNTED-64-LABEL: entry
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; COUNTED-64: statepoint
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; COUNTED-64-LABEL: loop
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; COUNTED-64: statepoint
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; COUNTED-64-LABEL: exit
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entry:
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br label %loop
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loop:
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%counter = phi i64 [ 0 , %entry ], [ %counter.inc , %loop ]
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%counter.inc = add i64 %counter, 1
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%counter.cmp = icmp sle i64 %counter.inc, %upper
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br i1 %counter.cmp, label %loop, label %exit
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exit:
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ret void
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}
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; This function is inlined when inserting a poll.
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declare void @do_safepoint()
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define void @gc.safepoint_poll() {
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; CHECK-LABEL: gc.safepoint_poll
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entry:
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call void @do_safepoint()
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ret void
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} |