0074a462f1
The profiling of the LLVM Test-suite reveals that a significant portion, specifically 14,090 out of 139,323, loop nests were identified as non-viable candidates for transformation, leading to the transform exiting from isComputableLoopNest() without any action. More importantly, dependence information was computed for these loop nests before reaching the function isComputableLoopNest(), which does not require DI and relies solely on scalar evolution (SE). To enhance compile-time efficiency, this patch moves the call to isComputableLoopNest() earlier in the control-flow, thereby avoiding unnecessary dependence calculations. The impact of this change is evident on the compile-time-tracker, with the overall geometric mean improvement recorded at 0.11%, while the lencode benchmark gets a more substantial benefit of 0.44%. This improvement can be tracked in the isc-ln-exp-2 branch under my repo.
53 lines
1.1 KiB
LLVM
53 lines
1.1 KiB
LLVM
; RUN: opt %s -passes='loop-interchange' -pass-remarks=loop-interchange -disable-output 2>&1 | FileCheck --allow-empty %s
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target triple = "aarch64-unknown-linux-gnu"
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; CHECK-NOT: Computed dependence info, invoking the transform.
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; For the below test, backedge count cannot be computed.
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; Computing backedge count requires only SCEV and should
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; not require dependence info.
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;
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; void bar(int m, int n) {
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; for (unsigned int i = 0; i < m; ++i) {
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; for (unsigned int j = 0; j < m; ++j) {
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; // dummy code
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; }
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; }
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;}
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define void @bar(i32 %m, i32 %n)
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{
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entry:
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br label %outer.header
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outer.header:
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%m_temp1 = phi i32 [%m, %entry], [%m_temp, %outer.latch]
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br label %inner.header
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inner.header:
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%n_temp1 = phi i32 [%n, %outer.header], [%n_temp, %inner.latch]
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br label %body
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body:
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; dummy code
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br label %inner.latch
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inner.latch:
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%n_temp = add i32 %n_temp1, 1
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%cmp2 = icmp eq i32 %n_temp, 1
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br i1 %cmp2, label %outer.latch, label %inner.header
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outer.latch:
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%m_temp = add i32 %n, 1
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%cmp3 = icmp eq i32 %m_temp, 1
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br i1 %cmp3, label %exit, label %outer.header
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exit:
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ret void
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}
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