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llvm-project/polly/test/CodeGen/phi_loop_carried_float.ll
Michael Kruse 7a0f7dbf2d [Polly] Introduce PhaseManager and remove LPM support (#125442) (#167560)
Reapply of a22d1c2225. Using this PR for
pre-merge CI.

Instead of relying on any pass manager to schedule Polly's passes, add
Polly's own pipeline manager which is seen as a monolithic pass in
LLVM's pass manager. Polly's former passes are now phases of the new
PhaseManager component.

Relying on LLVM's pass manager (the legacy as well as the New Pass
Manager) to manage Polly's phases never was a good fit that the
PhaseManager resolves:

* Polly passes were modifying analysis results, in particular RegionInfo
and ScopInfo. This means that there was not just one unique and
"definite" analysis result, the actual result depended on which analyses
ran prior, and the pass manager was not allowed to throw away cached
analyses or prior SCoP optimizations would have been forgotten. The LLVM
pass manger's persistance of analysis results is not contractual but
designed for caching.

* Polly depends on a particular execution order of passes and regions
(e.g. regression tests, invalidation of consecutive SCoPs). LLVM's pass
manager does not guarantee any excecution order.

* Polly does not completely preserve DominatorTree, RegionInfo,
LoopInfo, or ScalarEvolution, but only as-needed for Polly's own uses.
Because the ScopDetection object stores references to those analyses, it
still had to lie to the pass manager that they would be preserved, or
the pass manager would have released and recomputed the invalidated
analysis objects that ScopDetection/ScopInfo was still referencing. To
ensure that no non-Polly pass would see these not-completely-preserved
analyses, all analyses still had to be thrown away after the
ScopPassManager, respectively with a BarrierNoopPass in case of the LPM.
 
* The NPM's PassInstrumentation wraps the IR unit into an `llvm::Any`
object, but implementations such as PrintIRInstrumentation call
llvm_unreachable on encountering an unknown IR unit, such as SCoPs, with
no extension points to add support. Hence LLVM crashes when dumping IR
between SCoP passes (such as `-print-before-changed` with Polly being
active).

The new PhaseManager uses some command line options that previously
belonged to Polly's legacy passes, such as `-polly-print-detect` (so the
option will continue to work). Hence the LPM support is incompatible
with the new approach and support for it is removed.
2025-11-14 00:45:54 +01:00

69 lines
2.3 KiB
LLVM

; RUN: opt %loadNPMPolly -S '-passes=polly<no-default-opts>' < %s | FileCheck %s
;
; float f(float *A, int N) {
; float tmp = 0;
; for (int i = 0; i < N; i++)
; tmp += A[i];
; }
;
; CHECK: bb:
; CHECK-NOT: %tmp7{{[.*]}} = alloca float
; CHECK-DAG: %tmp.0.s2a = alloca float
; CHECK-NOT: %tmp7{{[.*]}} = alloca float
; CHECK-DAG: %tmp.0.phiops = alloca float
; CHECK-NOT: %tmp7{{[.*]}} = alloca float
; CHECK-LABEL: exit:
; CHECK-NEXT: ret
; CHECK-LABEL: polly.start:
; CHECK-NEXT: store float 0.000000e+00, ptr %tmp.0.phiops
; CHECK-NEXT: sext
; CHECK-LABEL: polly.exiting:
; CHECK-NEXT: br label %polly.merge_new_and_old
; CHECK-LABEL: polly.stmt.bb1{{[0-9]*}}:
; CHECK-NEXT: %tmp.0.phiops.reload[[R1:[0-9]*]] = load float, ptr %tmp.0.phiops
; CHECK: store float %tmp.0.phiops.reload[[R1]], ptr %tmp.0.s2a
; CHECK-LABEL: polly.stmt.bb4:
; CHECK: %tmp.0.s2a.reload[[R3:[0-9]*]] = load float, ptr %tmp.0.s2a
; CHECK: %tmp[[R5:[0-9]*]]_p_scalar_ = load float, ptr %scevgep, align 4, !alias.scope !2, !noalias !5
; CHECK: %p_tmp[[R4:[0-9]*]] = fadd float %tmp.0.s2a.reload[[R3]], %tmp[[R5]]_p_scalar_
; CHECK: store float %p_tmp[[R4]], ptr %tmp.0.phiops
; CHECK-LABEL: polly.stmt.bb1{{[0-9]*}}:
; CHECK-NEXT: %tmp.0.phiops.reload[[R2:[0-9]*]] = load float, ptr %tmp.0.phiops
; CHECK: store float %tmp.0.phiops.reload[[R2]], ptr %tmp.0.s2a
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
define void @f(ptr %A, i32 %N) {
bb:
%tmp = sext i32 %N to i64
br label %bb1
bb1: ; preds = %bb4, %bb
%indvars.iv = phi i64 [ %indvars.iv.next, %bb4 ], [ 0, %bb ]
%tmp.0 = phi float [ 0.000000e+00, %bb ], [ %tmp7, %bb4 ]
%tmp2 = icmp slt i64 %indvars.iv, %tmp
br i1 %tmp2, label %bb3, label %bb8
bb3: ; preds = %bb1
br label %bb4
bb4: ; preds = %bb3
%tmp5 = getelementptr inbounds float, ptr %A, i64 %indvars.iv
%tmp6 = load float, ptr %tmp5, align 4
%tmp7 = fadd float %tmp.0, %tmp6
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
br label %bb1
bb8: ; preds = %bb1
br label %exit
exit:
ret void
}