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This changes the SelectionDAG scheduling preference to source order. Soon, the SelectionDAG scheduler can be bypassed saving a nice chunk of compile time. Performance differences that result from this change are often a consequence of register coalescing. The register coalescer is far from perfect. Bugs can be filed for deficiencies. On x86 SandyBridge/Haswell, the source order schedule is often preserved, particularly for small blocks. Register pressure is generally improved over the SD scheduler's ILP mode. However, we are still able to handle large blocks that require latency hiding, unlike the SD scheduler's BURR mode. MI scheduler also attempts to discover the critical path in single-block loops and adjust heuristics accordingly. The MI scheduler relies on the new machine model. This is currently unimplemented for AVX, so we may not be generating the best code yet. Unit tests are updated so they don't depend on SD scheduling heuristics. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192750 91177308-0d34-0410-b5e6-96231b3b80d8
74 lines
2.1 KiB
LLVM
74 lines
2.1 KiB
LLVM
; RUN: llc < %s -mcpu=generic -march=x86 | FileCheck %s
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%struct._obstack_chunk = type { i8*, %struct._obstack_chunk*, [4 x i8] }
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%struct.obstack = type { i32, %struct._obstack_chunk*, i8*, i8*, i8*, i32, i32, %struct._obstack_chunk* (...)*, void (...)*, i8*, i8 }
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@stmt_obstack = external global %struct.obstack ; <%struct.obstack*> [#uses=1]
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; This should just not crash.
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define void @test1() nounwind {
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entry:
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br i1 true, label %cond_true, label %cond_next
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cond_true: ; preds = %entry
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%new_size.0.i = select i1 false, i32 0, i32 0 ; <i32> [#uses=1]
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%tmp.i = load i32* bitcast (i8* getelementptr (%struct.obstack* @stmt_obstack, i32 0, i32 10) to i32*) ; <i32> [#uses=1]
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%tmp.i.upgrd.1 = trunc i32 %tmp.i to i8 ; <i8> [#uses=1]
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%tmp21.i = and i8 %tmp.i.upgrd.1, 1 ; <i8> [#uses=1]
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%tmp22.i = icmp eq i8 %tmp21.i, 0 ; <i1> [#uses=1]
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br i1 %tmp22.i, label %cond_false30.i, label %cond_true23.i
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cond_true23.i: ; preds = %cond_true
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ret void
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cond_false30.i: ; preds = %cond_true
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%tmp35.i = tail call %struct._obstack_chunk* null( i32 %new_size.0.i ) ; <%struct._obstack_chunk*> [#uses=0]
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ret void
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cond_next: ; preds = %entry
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ret void
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}
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define i32 @test2(i16* %P, i16* %Q) nounwind {
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%A = load i16* %P, align 4 ; <i16> [#uses=11]
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%C = zext i16 %A to i32 ; <i32> [#uses=1]
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%D = and i32 %C, 255 ; <i32> [#uses=1]
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br label %L
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L:
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store i16 %A, i16* %Q
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ret i32 %D
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; CHECK-LABEL: test2:
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; CHECK: movl 4(%esp), %eax
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; CHECK-NEXT: movzwl (%eax), %e{{..}}
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}
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; rdar://10554090
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; xor in exit block will be CSE'ed and load will be folded to xor in entry.
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define i1 @test3(i32* %P, i32* %Q) nounwind {
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; CHECK-LABEL: test3:
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; CHECK: movl 8(%esp), %e
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; CHECK: movl 4(%esp), %e
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; CHECK: xorl (%e
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; CHECK: j
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entry:
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%0 = load i32* %P, align 4
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%1 = load i32* %Q, align 4
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%2 = xor i32 %0, %1
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%3 = and i32 %2, 89947
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%4 = icmp eq i32 %3, 0
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br i1 %4, label %exit, label %land.end
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exit:
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%shr.i.i19 = xor i32 %1, %0
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%5 = and i32 %shr.i.i19, 3456789123
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%6 = icmp eq i32 %5, 0
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br label %land.end
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land.end:
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%7 = phi i1 [ %6, %exit ], [ false, %entry ]
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ret i1 %7
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}
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