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LoopLoadElim: re-org tests after invalid llvm#96656 (llvm#97598)
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After pr96656.ll were added to LAA and LoopVersioning, it was decided
that the bug is in a caller of LoopVersioning, not in LAA or
LoopVersioning itself. The new candidate was LoopLoadElim, but llvm#96656
has since been marked invalid. Hence, re-organize the added tests to
avoid confusion, and the testcase from the investigation to
LoopLoadElim.
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@artagnon @xgupta
artagnon authored and xgupta committed Oct 4, 2024
1 parent bb4f69c commit f707cfb
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Showing 4 changed files with 175 additions and 78 deletions.
49 changes: 0 additions & 49 deletions llvm/test/Analysis/LoopAccessAnalysis/pr96656.ll
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48 changes: 48 additions & 0 deletions llvm/test/Analysis/LoopAccessAnalysis/symbolic-stride.ll
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Expand Up @@ -223,6 +223,54 @@ exit:
ret void
}

define double @single_iteration_unknown_stride(i32 %x, ptr %y, i1 %cond) {
; CHECK-LABEL: 'single_iteration_unknown_stride'
; CHECK-NEXT: loop.body:
; CHECK-NEXT: Memory dependences are safe
; CHECK-NEXT: Dependences:
; CHECK-NEXT: Run-time memory checks:
; CHECK-NEXT: Grouped accesses:
; CHECK-EMPTY:
; CHECK-NEXT: Non vectorizable stores to invariant address were not found in loop.
; CHECK-NEXT: SCEV assumptions:
; CHECK-NEXT: Equal predicate: %x == 1
; CHECK-EMPTY:
; CHECK-NEXT: Expressions re-written:
; CHECK-NEXT: [PSE] %gep10 = getelementptr double, ptr %gep8, i64 %mul:
; CHECK-NEXT: {(8 + %y),+,(8 * (sext i32 %x to i64))<nsw>}<%loop.body>
; CHECK-NEXT: --> {(8 + %y),+,8}<%loop.body>
;
entry:
br i1 %cond, label %noloop.exit, label %loop.ph

loop.ph: ; preds = %entry
%sext7 = sext i32 %x to i64
%gep8 = getelementptr i8, ptr %y, i64 8
br label %loop.body

loop.body: ; preds = %loop.body, %loop.ph
%iv = phi i64 [ 0, %loop.ph ], [ %iv.next, %loop.body ]
%mul = mul i64 %iv, %sext7
%gep10 = getelementptr double, ptr %gep8, i64 %mul
%load11 = load double, ptr %gep10, align 8
store double %load11, ptr %y, align 8
%iv.next = add i64 %iv, 1
%icmp = icmp eq i64 %iv, 0
br i1 %icmp, label %loop.exit, label %loop.body

noloop.exit: ; preds = %entry
%sext = sext i32 %x to i64
%gep = getelementptr double, ptr %y, i64 %sext
%load5 = load double, ptr %gep, align 8
ret double %load5

loop.exit: ; preds = %loop.body
%sext2 = sext i32 %x to i64
%gep2 = getelementptr double, ptr %y, i64 %sext2
%load6 = load double, ptr %gep2, align 8
ret double %load6
}

; A loop with two symbolic strides.
define void @two_strides(ptr noalias %A, ptr noalias %B, i64 %N, i64 %stride.1, i64 %stride.2) {
; CHECK-LABEL: 'two_strides'
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91 changes: 91 additions & 0 deletions llvm/test/Transforms/LoopLoadElim/unknown-stride-known-dep.ll
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@@ -0,0 +1,91 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt -passes=loop-load-elim -S %s | FileCheck %s

; The test was originally written as part of the investigation of #96656.
; The bug has now been marked as invalid, and we keep the test to show
; LLE's operation on known dependence returned by LAA.

define void @unknown_stride_known_dependence(ptr %x, ptr %y, i1 %cond) {
; CHECK-LABEL: define void @unknown_stride_known_dependence(
; CHECK-SAME: ptr [[X:%.*]], ptr [[Y:%.*]], i1 [[COND:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: [[LOAD:%.*]] = load i32, ptr [[X]], align 4
; CHECK-NEXT: br i1 [[COND]], label %[[NOLOOP_EXIT:.*]], label %[[LOOP_LVER_CHECK:.*]]
; CHECK: [[LOOP_LVER_CHECK]]:
; CHECK-NEXT: [[SEXT_X:%.*]] = sext i32 [[LOAD]] to i64
; CHECK-NEXT: [[GEP_8:%.*]] = getelementptr i8, ptr [[Y]], i64 8
; CHECK-NEXT: [[GEP_16:%.*]] = getelementptr i8, ptr [[Y]], i64 16
; CHECK-NEXT: [[IDENT_CHECK:%.*]] = icmp ne i32 [[LOAD]], 1
; CHECK-NEXT: br i1 [[IDENT_CHECK]], label %[[LOOP_PH_LVER_ORIG:.*]], label %[[LOOP_PH:.*]]
; CHECK: [[LOOP_PH_LVER_ORIG]]:
; CHECK-NEXT: br label %[[LOOP_LVER_ORIG:.*]]
; CHECK: [[LOOP_LVER_ORIG]]:
; CHECK-NEXT: [[IV_LVER_ORIG:%.*]] = phi i64 [ 0, %[[LOOP_PH_LVER_ORIG]] ], [ [[IV_NEXT_LVER_ORIG:%.*]], %[[LOOP_LVER_ORIG]] ]
; CHECK-NEXT: [[MUL_LVER_ORIG:%.*]] = mul i64 [[IV_LVER_ORIG]], [[SEXT_X]]
; CHECK-NEXT: [[GEP_8_MUL_LVER_ORIG:%.*]] = getelementptr double, ptr [[GEP_8]], i64 [[MUL_LVER_ORIG]]
; CHECK-NEXT: [[LOAD_8_LVER_ORIG:%.*]] = load double, ptr [[GEP_8_MUL_LVER_ORIG]], align 8
; CHECK-NEXT: [[GEP_16_MUL_LVER_ORIG:%.*]] = getelementptr double, ptr [[GEP_16]], i64 [[MUL_LVER_ORIG]]
; CHECK-NEXT: store double [[LOAD_8_LVER_ORIG]], ptr [[GEP_16_MUL_LVER_ORIG]], align 8
; CHECK-NEXT: [[IV_NEXT_LVER_ORIG]] = add i64 [[IV_LVER_ORIG]], 1
; CHECK-NEXT: [[ICMP_LVER_ORIG:%.*]] = icmp eq i64 [[IV_LVER_ORIG]], 1
; CHECK-NEXT: br i1 [[ICMP_LVER_ORIG]], label %[[EXIT_LOOPEXIT_LOOPEXIT:.*]], label %[[LOOP_LVER_ORIG]]
; CHECK: [[LOOP_PH]]:
; CHECK-NEXT: [[LOAD_INITIAL:%.*]] = load double, ptr [[GEP_8]], align 8
; CHECK-NEXT: br label %[[LOOP:.*]]
; CHECK: [[LOOP]]:
; CHECK-NEXT: [[STORE_FORWARDED:%.*]] = phi double [ [[LOAD_INITIAL]], %[[LOOP_PH]] ], [ [[STORE_FORWARDED]], %[[LOOP]] ]
; CHECK-NEXT: [[IV:%.*]] = phi i64 [ 0, %[[LOOP_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP]] ]
; CHECK-NEXT: [[MUL:%.*]] = mul i64 [[IV]], [[SEXT_X]]
; CHECK-NEXT: [[GEP_8_MUL:%.*]] = getelementptr double, ptr [[GEP_8]], i64 [[MUL]]
; CHECK-NEXT: [[LOAD_8:%.*]] = load double, ptr [[GEP_8_MUL]], align 8
; CHECK-NEXT: [[GEP_16_MUL:%.*]] = getelementptr double, ptr [[GEP_16]], i64 [[MUL]]
; CHECK-NEXT: store double [[STORE_FORWARDED]], ptr [[GEP_16_MUL]], align 8
; CHECK-NEXT: [[IV_NEXT]] = add i64 [[IV]], 1
; CHECK-NEXT: [[ICMP:%.*]] = icmp eq i64 [[IV]], 1
; CHECK-NEXT: br i1 [[ICMP]], label %[[EXIT_LOOPEXIT_LOOPEXIT1:.*]], label %[[LOOP]]
; CHECK: [[NOLOOP_EXIT]]:
; CHECK-NEXT: [[SEXT:%.*]] = sext i32 [[LOAD]] to i64
; CHECK-NEXT: [[GEP_Y:%.*]] = getelementptr double, ptr [[Y]], i64 [[SEXT]]
; CHECK-NEXT: [[LOAD_Y:%.*]] = load double, ptr [[GEP_Y]], align 8
; CHECK-NEXT: store double [[LOAD_Y]], ptr [[X]], align 8
; CHECK-NEXT: br label %[[EXIT:.*]]
; CHECK: [[EXIT_LOOPEXIT_LOOPEXIT]]:
; CHECK-NEXT: br label %[[EXIT_LOOPEXIT:.*]]
; CHECK: [[EXIT_LOOPEXIT_LOOPEXIT1]]:
; CHECK-NEXT: br label %[[EXIT_LOOPEXIT]]
; CHECK: [[EXIT_LOOPEXIT]]:
; CHECK-NEXT: br label %[[EXIT]]
; CHECK: [[EXIT]]:
; CHECK-NEXT: ret void
;
entry:
%load = load i32, ptr %x, align 4
br i1 %cond, label %noloop.exit, label %loop.ph

loop.ph: ; preds = %entry
%sext.x = sext i32 %load to i64
%gep.8 = getelementptr i8, ptr %y, i64 8
%gep.16 = getelementptr i8, ptr %y, i64 16
br label %loop

loop: ; preds = %loop, %loop.ph
%iv = phi i64 [ 0, %loop.ph ], [ %iv.next, %loop ]
%mul = mul i64 %iv, %sext.x
%gep.8.mul = getelementptr double, ptr %gep.8, i64 %mul
%load.8 = load double, ptr %gep.8.mul, align 8
%gep.16.mul = getelementptr double, ptr %gep.16, i64 %mul
store double %load.8, ptr %gep.16.mul
%iv.next = add i64 %iv, 1
%icmp = icmp eq i64 %iv, 1
br i1 %icmp, label %exit, label %loop

noloop.exit: ; preds = %loop.ph
%sext = sext i32 %load to i64
%gep.y = getelementptr double, ptr %y, i64 %sext
%load.y = load double, ptr %gep.y
store double %load.y, ptr %x
br label %exit

exit: ; preds = %loop.body
ret void
}
65 changes: 36 additions & 29 deletions ...test/Transforms/LoopVersioning/pr96656.ll → ...sforms/LoopVersioning/single-iteration.ll
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Original file line number Diff line number Diff line change
@@ -1,16 +1,20 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt -passes=loop-versioning -S %s | FileCheck %s

define void @lver.check.unnecessary(ptr %arg, ptr %arg1, i1 %arg2) {
; CHECK-LABEL: define void @lver.check.unnecessary(
; CHECK-SAME: ptr [[ARG:%.*]], ptr [[ARG1:%.*]], i1 [[ARG2:%.*]]) {
; Callers should not call LoopVersioning on single-iteration loops, as it
; is very likely not profitable.
; LoopVersioning faithfully versions single-iteration loops when the stride
; is unknown.

define double @single_iteration_unknown_stride(i32 %x, ptr %y, i1 %cond) {
; CHECK-LABEL: define double @single_iteration_unknown_stride(
; CHECK-SAME: i32 [[X:%.*]], ptr [[Y:%.*]], i1 [[COND:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: [[LOAD:%.*]] = load i32, ptr [[ARG]], align 4
; CHECK-NEXT: br i1 [[ARG2]], label %[[NOLOOP_EXIT:.*]], label %[[LOOP_BODY_LVER_CHECK:.*]]
; CHECK-NEXT: br i1 [[COND]], label %[[NOLOOP_EXIT:.*]], label %[[LOOP_BODY_LVER_CHECK:.*]]
; CHECK: [[LOOP_BODY_LVER_CHECK]]:
; CHECK-NEXT: [[SEXT7:%.*]] = sext i32 [[LOAD]] to i64
; CHECK-NEXT: [[GEP8:%.*]] = getelementptr i8, ptr [[ARG1]], i64 8
; CHECK-NEXT: [[IDENT_CHECK:%.*]] = icmp ne i32 [[LOAD]], 1
; CHECK-NEXT: [[SEXT7:%.*]] = sext i32 [[X]] to i64
; CHECK-NEXT: [[GEP8:%.*]] = getelementptr i8, ptr [[Y]], i64 8
; CHECK-NEXT: [[IDENT_CHECK:%.*]] = icmp ne i32 [[X]], 1
; CHECK-NEXT: br i1 [[IDENT_CHECK]], label %[[LOOP_BODY_PH_LVER_ORIG:.*]], label %[[LOOP_BODY_PH:.*]]
; CHECK: [[LOOP_BODY_PH_LVER_ORIG]]:
; CHECK-NEXT: br label %[[LOOP_BODY_LVER_ORIG:.*]]
Expand All @@ -19,7 +23,7 @@ define void @lver.check.unnecessary(ptr %arg, ptr %arg1, i1 %arg2) {
; CHECK-NEXT: [[MUL_LVER_ORIG:%.*]] = mul i64 [[PHI_LVER_ORIG]], [[SEXT7]]
; CHECK-NEXT: [[GEP10_LVER_ORIG:%.*]] = getelementptr double, ptr [[GEP8]], i64 [[MUL_LVER_ORIG]]
; CHECK-NEXT: [[LOAD11_LVER_ORIG:%.*]] = load double, ptr [[GEP10_LVER_ORIG]], align 8
; CHECK-NEXT: store double [[LOAD11_LVER_ORIG]], ptr [[ARG1]], align 8
; CHECK-NEXT: store double [[LOAD11_LVER_ORIG]], ptr [[Y]], align 8
; CHECK-NEXT: [[ADD_LVER_ORIG]] = add i64 [[PHI_LVER_ORIG]], 1
; CHECK-NEXT: [[ICMP_LVER_ORIG:%.*]] = icmp eq i64 [[PHI_LVER_ORIG]], 0
; CHECK-NEXT: br i1 [[ICMP_LVER_ORIG]], label %[[LOOP_EXIT_LOOPEXIT:.*]], label %[[LOOP_BODY_LVER_ORIG]]
Expand All @@ -30,49 +34,52 @@ define void @lver.check.unnecessary(ptr %arg, ptr %arg1, i1 %arg2) {
; CHECK-NEXT: [[MUL:%.*]] = mul i64 [[PHI]], [[SEXT7]]
; CHECK-NEXT: [[GEP10:%.*]] = getelementptr double, ptr [[GEP8]], i64 [[MUL]]
; CHECK-NEXT: [[LOAD11:%.*]] = load double, ptr [[GEP10]], align 8
; CHECK-NEXT: store double [[LOAD11]], ptr [[ARG1]], align 8
; CHECK-NEXT: store double [[LOAD11]], ptr [[Y]], align 8
; CHECK-NEXT: [[ADD]] = add i64 [[PHI]], 1
; CHECK-NEXT: [[ICMP:%.*]] = icmp eq i64 [[PHI]], 0
; CHECK-NEXT: br i1 [[ICMP]], label %[[LOOP_EXIT_LOOPEXIT1:.*]], label %[[LOOP_BODY]]
; CHECK: [[NOLOOP_EXIT]]:
; CHECK-NEXT: [[SEXT:%.*]] = sext i32 [[LOAD]] to i64
; CHECK-NEXT: [[GEP:%.*]] = getelementptr double, ptr [[ARG1]], i64 [[SEXT]]
; CHECK-NEXT: [[SEXT:%.*]] = sext i32 [[X]] to i64
; CHECK-NEXT: [[GEP:%.*]] = getelementptr double, ptr [[Y]], i64 [[SEXT]]
; CHECK-NEXT: [[LOAD5:%.*]] = load double, ptr [[GEP]], align 8
; CHECK-NEXT: store double [[LOAD5]], ptr [[ARG]], align 8
; CHECK-NEXT: ret void
; CHECK-NEXT: ret double [[LOAD5]]
; CHECK: [[LOOP_EXIT_LOOPEXIT]]:
; CHECK-NEXT: br label %[[LOOP_EXIT:.*]]
; CHECK: [[LOOP_EXIT_LOOPEXIT1]]:
; CHECK-NEXT: br label %[[LOOP_EXIT]]
; CHECK: [[LOOP_EXIT]]:
; CHECK-NEXT: ret void
; CHECK-NEXT: [[SEXT2:%.*]] = sext i32 [[X]] to i64
; CHECK-NEXT: [[GEP2:%.*]] = getelementptr double, ptr [[Y]], i64 [[SEXT2]]
; CHECK-NEXT: [[LOAD6:%.*]] = load double, ptr [[GEP2]], align 8
; CHECK-NEXT: ret double [[LOAD6]]
;
entry:
%load = load i32, ptr %arg, align 4
br i1 %arg2, label %noloop.exit, label %loop.ph
br i1 %cond, label %noloop.exit, label %loop.ph

loop.ph: ; preds = %entry
%sext7 = sext i32 %load to i64
%gep8 = getelementptr i8, ptr %arg1, i64 8
%sext7 = sext i32 %x to i64
%gep8 = getelementptr i8, ptr %y, i64 8
br label %loop.body

loop.body: ; preds = %loop.body, %loop.ph
%phi = phi i64 [ 0, %loop.ph ], [ %add, %loop.body ]
%mul = mul i64 %phi, %sext7
%iv = phi i64 [ 0, %loop.ph ], [ %iv.next, %loop.body ]
%mul = mul i64 %iv, %sext7
%gep10 = getelementptr double, ptr %gep8, i64 %mul
%load11 = load double, ptr %gep10, align 8
store double %load11, ptr %arg1, align 8
%add = add i64 %phi, 1
%icmp = icmp eq i64 %phi, 0
store double %load11, ptr %y, align 8
%iv.next = add i64 %iv, 1
%icmp = icmp eq i64 %iv, 0
br i1 %icmp, label %loop.exit, label %loop.body

noloop.exit: ; preds = %entry
%sext = sext i32 %load to i64
%gep = getelementptr double, ptr %arg1, i64 %sext
%sext = sext i32 %x to i64
%gep = getelementptr double, ptr %y, i64 %sext
%load5 = load double, ptr %gep, align 8
store double %load5, ptr %arg, align 8
ret void
ret double %load5

loop.exit: ; preds = %loop.body
ret void
%sext2 = sext i32 %x to i64
%gep2 = getelementptr double, ptr %y, i64 %sext2
%load6 = load double, ptr %gep2, align 8
ret double %load6
}

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