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| -rw-r--r-- | llvm/test/Transforms/LoopUnroll/unroll-cost-symbolic-execute.ll | 310 |
1 files changed, 310 insertions, 0 deletions
diff --git a/llvm/test/Transforms/LoopUnroll/unroll-cost-symbolic-execute.ll b/llvm/test/Transforms/LoopUnroll/unroll-cost-symbolic-execute.ll new file mode 100644 index 0000000..865f093 --- /dev/null +++ b/llvm/test/Transforms/LoopUnroll/unroll-cost-symbolic-execute.ll @@ -0,0 +1,310 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py +; RUN: opt -loop-unroll -S -unroll-threshold=120 -unroll-max-iteration-count-to-analyze=100 < %s | FileCheck %s + +; TODO: None of the if.false blocks are reachable, it would be nice if +; the output of unrolling made this obvious and didn't rely on other +; passes to cleanup code the cost model already knew was dead. + +@G = global i32 0 + +; Symbolic simplification can prove the value of %zext on first +; iteration, and can prove that it's loop invariant on the second +define i32 @test_symbolic_simplify(i32 %limit) { +; CHECK-LABEL: @test_symbolic_simplify( +; CHECK-NEXT: entry: +; CHECK-NEXT: br label [[LOOP_PEEL_BEGIN:%.*]] +; CHECK: loop.peel.begin: +; CHECK-NEXT: br label [[LOOP_PEEL:%.*]] +; CHECK: loop.peel: +; CHECK-NEXT: [[SUB_PEEL:%.*]] = sub i32 [[LIMIT:%.*]], 0 +; CHECK-NEXT: [[CMP_PEEL:%.*]] = icmp eq i32 [[SUB_PEEL]], [[LIMIT]] +; CHECK-NEXT: [[ZEXT_PEEL:%.*]] = sext i1 [[CMP_PEEL]] to i32 +; CHECK-NEXT: store i32 [[ZEXT_PEEL]], i32* @G, align 4 +; CHECK-NEXT: [[IV_NEXT_PEEL:%.*]] = add i32 0, 1 +; CHECK-NEXT: [[LOOP_COND_PEEL:%.*]] = icmp ne i32 0, 80 +; CHECK-NEXT: br i1 [[LOOP_COND_PEEL]], label [[LOOP_PEEL_NEXT:%.*]], label [[DONE:%.*]] +; CHECK: loop.peel.next: +; CHECK-NEXT: br label [[LOOP_PEEL_NEXT1:%.*]] +; CHECK: loop.peel.next1: +; CHECK-NEXT: br label [[ENTRY_PEEL_NEWPH:%.*]] +; CHECK: entry.peel.newph: +; CHECK-NEXT: br label [[LOOP:%.*]] +; CHECK: loop: +; CHECK-NEXT: [[IV:%.*]] = phi i32 [ [[IV_NEXT_PEEL]], [[ENTRY_PEEL_NEWPH]] ], [ [[IV_NEXT:%.*]], [[LOOP]] ] +; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 0, [[LIMIT]] +; CHECK-NEXT: [[ZEXT:%.*]] = sext i1 [[CMP]] to i32 +; CHECK-NEXT: store i32 [[ZEXT]], i32* @G, align 4 +; CHECK-NEXT: [[IV_NEXT]] = add nuw nsw i32 [[IV]], 1 +; CHECK-NEXT: [[LOOP_COND:%.*]] = icmp ne i32 [[IV]], 80 +; CHECK-NEXT: br i1 [[LOOP_COND]], label [[LOOP]], label [[DONE_LOOPEXIT:%.*]], !llvm.loop [[LOOP0:![0-9]+]] +; CHECK: done.loopexit: +; CHECK-NEXT: [[ZEXT_LCSSA_PH:%.*]] = phi i32 [ [[ZEXT]], [[LOOP]] ] +; CHECK-NEXT: br label [[DONE]] +; CHECK: done: +; CHECK-NEXT: [[ZEXT_LCSSA:%.*]] = phi i32 [ [[ZEXT_PEEL]], [[LOOP_PEEL]] ], [ [[ZEXT_LCSSA_PH]], [[DONE_LOOPEXIT]] ] +; CHECK-NEXT: ret i32 [[ZEXT_LCSSA]] +; +entry: + br label %loop + +loop: ; preds = %backedge, %entry + %phi = phi i32 [ 0, %entry ], [ %limit, %loop ] + %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop ] + %sub = sub i32 %limit, %phi + %cmp = icmp eq i32 %sub, %limit + %zext = sext i1 %cmp to i32 + store i32 %zext, i32* @G + %iv.next = add i32 %iv, 1 + %loop.cond = icmp ne i32 %iv, 80 + br i1 %loop.cond, label %loop, label %done + +done: ; preds = %backedge + ret i32 %zext +} + +; Use symbolic value facts to prune unreachable (expensive) paths +; through the loop. +define i32 @test_symbolic_path(i32 %limit) { +; CHECK-LABEL: @test_symbolic_path( +; CHECK-NEXT: entry: +; CHECK-NEXT: br label [[LOOP:%.*]] +; CHECK: loop: +; CHECK-NEXT: [[SUM:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[SUM_NEXT:%.*]], [[BACKEDGE:%.*]] ] +; CHECK-NEXT: [[IV:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[IV_NEXT:%.*]], [[BACKEDGE]] ] +; CHECK-NEXT: [[SUB:%.*]] = sub i32 [[LIMIT:%.*]], [[SUM]] +; CHECK-NEXT: [[IS_POSITIVE:%.*]] = icmp eq i32 [[SUB]], [[LIMIT]] +; CHECK-NEXT: br i1 [[IS_POSITIVE]], label [[BACKEDGE]], label [[IF_FALSE:%.*]] +; CHECK: if.false: +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: br label [[BACKEDGE]] +; CHECK: backedge: +; CHECK-NEXT: [[HIDDEN_ZERO:%.*]] = sub i32 [[LIMIT]], [[SUB]] +; CHECK-NEXT: [[SUM_NEXT]] = add i32 [[SUM]], [[HIDDEN_ZERO]] +; CHECK-NEXT: [[IV_NEXT]] = add i32 [[IV]], 1 +; CHECK-NEXT: [[LOOP_COND:%.*]] = icmp ne i32 [[IV]], 8 +; CHECK-NEXT: br i1 [[LOOP_COND]], label [[LOOP]], label [[DONE:%.*]] +; CHECK: done: +; CHECK-NEXT: [[SUM_NEXT_LCSSA:%.*]] = phi i32 [ [[SUM_NEXT]], [[BACKEDGE]] ] +; CHECK-NEXT: ret i32 [[SUM_NEXT_LCSSA]] +; +entry: + br label %loop + +loop: ; preds = %backedge, %entry + %sum = phi i32 [ 0, %entry ], [ %sum.next, %backedge ] + %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ] + %sub = sub i32 %limit, %sum + %is.positive = icmp eq i32 %sub, %limit + br i1 %is.positive, label %backedge, label %if.false + +if.false: ; preds = %loop + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + br label %backedge + +backedge: ; preds = %if.false, %loop + %hidden_zero = sub i32 %limit, %sub + %sum.next = add i32 %sum, %hidden_zero + %iv.next = add i32 %iv, 1 + %loop.cond = icmp ne i32 %iv, 8 + br i1 %loop.cond, label %loop, label %done + +done: ; preds = %backedge + %sum.next.lcssa = phi i32 [ %sum.next, %backedge ] + ret i32 %sum.next.lcssa +} + +; A test to show the ability to simplify branches (even without general +; symbolic execution of the loop beyond constants) is still useful. +define i32 @test_dom_condition(i32 %limit) { +; CHECK-LABEL: @test_dom_condition( +; CHECK-NEXT: entry: +; CHECK-NEXT: [[LOOP_GUARD:%.*]] = icmp sge i32 [[LIMIT:%.*]], 0 +; CHECK-NEXT: br i1 [[LOOP_GUARD]], label [[LOOP_PREHEADER:%.*]], label [[FAILURE:%.*]] +; CHECK: loop.preheader: +; CHECK-NEXT: br label [[LOOP:%.*]] +; CHECK: loop: +; CHECK-NEXT: [[SUM:%.*]] = phi i32 [ [[SUM_NEXT:%.*]], [[BACKEDGE:%.*]] ], [ 0, [[LOOP_PREHEADER]] ] +; CHECK-NEXT: [[IV:%.*]] = phi i32 [ [[IV_NEXT:%.*]], [[BACKEDGE]] ], [ 0, [[LOOP_PREHEADER]] ] +; CHECK-NEXT: [[SUB:%.*]] = sub i32 0, [[SUM]] +; CHECK-NEXT: [[IS_POSITIVE:%.*]] = icmp sle i32 [[SUB]], [[LIMIT]] +; CHECK-NEXT: br i1 [[IS_POSITIVE]], label [[BACKEDGE]], label [[IF_FALSE:%.*]] +; CHECK: if.false: +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: br label [[BACKEDGE]] +; CHECK: backedge: +; CHECK-NEXT: [[SUM_NEXT]] = add i32 [[SUM]], [[SUB]] +; CHECK-NEXT: [[IV_NEXT]] = add i32 [[IV]], 1 +; CHECK-NEXT: [[LOOP_COND:%.*]] = icmp ne i32 [[IV]], 8 +; CHECK-NEXT: br i1 [[LOOP_COND]], label [[LOOP]], label [[DONE:%.*]] +; CHECK: done: +; CHECK-NEXT: [[SUM_NEXT_LCSSA:%.*]] = phi i32 [ [[SUM_NEXT]], [[BACKEDGE]] ] +; CHECK-NEXT: ret i32 [[SUM_NEXT_LCSSA]] +; CHECK: failure: +; CHECK-NEXT: unreachable +; +entry: + %loop_guard = icmp sge i32 %limit, 0 + br i1 %loop_guard, label %loop, label %failure + +loop: ; preds = %backedge, %entry + %sum = phi i32 [ 0, %entry ], [ %sum.next, %backedge ] + %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ] + %sub = sub i32 0, %sum + %is.positive = icmp sle i32 %sub, %limit + br i1 %is.positive, label %backedge, label %if.false + +if.false: ; preds = %loop + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + br label %backedge + +backedge: ; preds = %if.false, %loop + %sum.next = add i32 %sum, %sub + %iv.next = add i32 %iv, 1 + %loop.cond = icmp ne i32 %iv, 8 + br i1 %loop.cond, label %loop, label %done + +done: ; preds = %backedge + %sum.next.lcssa = phi i32 [ %sum.next, %backedge ] + ret i32 %sum.next.lcssa + +failure: + unreachable +} + +; We can symbolically evaluate %sub to %limit on first iteration, and +; to zero on all future iterations. +define i32 @test_both(i32 %limit) { +; CHECK-LABEL: @test_both( +; CHECK-NEXT: entry: +; CHECK-NEXT: [[LOOP_GUARD:%.*]] = icmp sge i32 [[LIMIT:%.*]], 0 +; CHECK-NEXT: br i1 [[LOOP_GUARD]], label [[LOOP_PREHEADER:%.*]], label [[FAILURE:%.*]] +; CHECK: loop.preheader: +; CHECK-NEXT: br label [[LOOP:%.*]] +; CHECK: loop: +; CHECK-NEXT: [[SUM:%.*]] = phi i32 [ [[SUM_NEXT:%.*]], [[BACKEDGE:%.*]] ], [ 0, [[LOOP_PREHEADER]] ] +; CHECK-NEXT: [[IV:%.*]] = phi i32 [ [[IV_NEXT:%.*]], [[BACKEDGE]] ], [ 0, [[LOOP_PREHEADER]] ] +; CHECK-NEXT: [[SUB:%.*]] = sub i32 [[LIMIT]], [[SUM]] +; CHECK-NEXT: [[IS_POSITIVE:%.*]] = icmp sge i32 [[SUB]], 0 +; CHECK-NEXT: br i1 [[IS_POSITIVE]], label [[BACKEDGE]], label [[IF_FALSE:%.*]] +; CHECK: if.false: +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: call void @foo() +; CHECK-NEXT: br label [[BACKEDGE]] +; CHECK: backedge: +; CHECK-NEXT: [[SUM_NEXT]] = add i32 [[SUM]], [[SUB]] +; CHECK-NEXT: [[IV_NEXT]] = add i32 [[IV]], 1 +; CHECK-NEXT: [[LOOP_COND:%.*]] = icmp ne i32 [[IV]], 8 +; CHECK-NEXT: br i1 [[LOOP_COND]], label [[LOOP]], label [[DONE:%.*]] +; CHECK: done: +; CHECK-NEXT: [[SUM_NEXT_LCSSA:%.*]] = phi i32 [ [[SUM_NEXT]], [[BACKEDGE]] ] +; CHECK-NEXT: ret i32 [[SUM_NEXT_LCSSA]] +; CHECK: failure: +; CHECK-NEXT: unreachable +; +entry: + %loop_guard = icmp sge i32 %limit, 0 + br i1 %loop_guard, label %loop, label %failure + +loop: ; preds = %backedge, %entry + %sum = phi i32 [ 0, %entry ], [ %sum.next, %backedge ] + %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ] + %sub = sub i32 %limit, %sum + %is.positive = icmp sge i32 %sub, 0 + br i1 %is.positive, label %backedge, label %if.false + +if.false: ; preds = %loop + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + call void @foo() + br label %backedge + +backedge: ; preds = %if.false, %loop + %sum.next = add i32 %sum, %sub + %iv.next = add i32 %iv, 1 + %loop.cond = icmp ne i32 %iv, 8 + br i1 %loop.cond, label %loop, label %done + +done: ; preds = %backedge + %sum.next.lcssa = phi i32 [ %sum.next, %backedge ] + ret i32 %sum.next.lcssa + +failure: + unreachable +} + +declare void @foo() |