[llvm] 3cbdfe4 - [SCEV] Add additional max BTC tests with loop guards.
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Mon Sep 21 09:41:48 PDT 2020
Author: Florian Hahn
Date: 2020-09-21T17:41:24+01:00
New Revision: 3cbdfe424fec923b5ac1912742c62c22f856fb29
URL: https://github.com/llvm/llvm-project/commit/3cbdfe424fec923b5ac1912742c62c22f856fb29
DIFF: https://github.com/llvm/llvm-project/commit/3cbdfe424fec923b5ac1912742c62c22f856fb29.diff
LOG: [SCEV] Add additional max BTC tests with loop guards.
Added:
Modified:
llvm/test/Analysis/ScalarEvolution/max-backedge-taken-count-guard-info.ll
Removed:
################################################################################
diff --git a/llvm/test/Analysis/ScalarEvolution/max-backedge-taken-count-guard-info.ll b/llvm/test/Analysis/ScalarEvolution/max-backedge-taken-count-guard-info.ll
index 0bbb8aace805..cb792335f181 100644
--- a/llvm/test/Analysis/ScalarEvolution/max-backedge-taken-count-guard-info.ll
+++ b/llvm/test/Analysis/ScalarEvolution/max-backedge-taken-count-guard-info.ll
@@ -24,12 +24,189 @@ exit:
ret void
}
+define void @test_guard_less_than_16_branches_flipped(i32* nocapture %a, i64 %i) {
+; CHECK-LABEL: Determining loop execution counts for: @test_guard_less_than_16_branches_flipped
+; CHECK-NEXT: Loop %loop: backedge-taken count is (15 + (-1 * %i))
+; CHECK-NEXT: Loop %loop: max backedge-taken count is -1
+; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is (15 + (-1 * %i))
+;
+entry:
+ %cmp3 = icmp ult i64 %i, 16
+ br i1 %cmp3, label %exit, label %loop
+
+loop:
+ %iv = phi i64 [ %iv.next, %loop ], [ %i, %entry ]
+ %idx = getelementptr inbounds i32, i32* %a, i64 %iv
+ store i32 1, i32* %idx, align 4
+ %iv.next = add nuw nsw i64 %iv, 1
+ %exitcond = icmp eq i64 %iv.next, 16
+ br i1 %exitcond, label %exit, label %loop
+
+exit:
+ ret void
+}
+
+define void @test_guard_uge_16_branches_flipped(i32* nocapture %a, i64 %i) {
+; CHECK-LABEL: Determining loop execution counts for: @test_guard_uge_16_branches_flipped
+; CHECK-NEXT: Loop %loop: backedge-taken count is (15 + (-1 * %i))
+; CHECK-NEXT: Loop %loop: max backedge-taken count is -1
+; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is (15 + (-1 * %i))
+;
+entry:
+ %cmp3 = icmp uge i64 %i, 16
+ br i1 %cmp3, label %exit, label %loop
+
+loop:
+ %iv = phi i64 [ %iv.next, %loop ], [ %i, %entry ]
+ %idx = getelementptr inbounds i32, i32* %a, i64 %iv
+ store i32 1, i32* %idx, align 4
+ %iv.next = add nuw nsw i64 %iv, 1
+ %exitcond = icmp eq i64 %iv.next, 16
+ br i1 %exitcond, label %exit, label %loop
+
+exit:
+ ret void
+}
+
+define void @test_multiple_const_guards_order1(i32* nocapture %a, i64 %i) {
+; CHECK-LABEL: @test_multiple_const_guards_order1
+; CHECK: Loop %loop: backedge-taken count is %i
+; CHECK-NEXT: Loop %loop: max backedge-taken count is -1
+; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is %i
+;
+entry:
+ %c.1 = icmp ult i64 %i, 16
+ br i1 %c.1, label %guardbb, label %exit
+
+guardbb:
+ %c.2 = icmp ult i64 %i, 10
+ br i1 %c.2, label %loop, label %exit
+
+loop:
+ %iv = phi i64 [ %iv.next, %loop ], [ 0, %guardbb ]
+ %idx = getelementptr inbounds i32, i32* %a, i64 %iv
+ store i32 1, i32* %idx, align 4
+ %iv.next = add nuw nsw i64 %iv, 1
+ %exitcond = icmp eq i64 %iv, %i
+ br i1 %exitcond, label %exit, label %loop
+
+exit:
+ ret void
+}
+
+define void @test_multiple_const_guards_order2(i32* nocapture %a, i64 %i) {
+; CHECK-LABEL: @test_multiple_const_guards_order2
+; CHECK: Loop %loop: backedge-taken count is %i
+; CHECK-NEXT: Loop %loop: max backedge-taken count is -1
+; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is %i
+;
+entry:
+ %c.1 = icmp ult i64 %i, 10
+ br i1 %c.1, label %guardbb, label %exit
+
+guardbb:
+ %c.2 = icmp ult i64 %i, 16
+ br i1 %c.2, label %loop, label %exit
+
+loop:
+ %iv = phi i64 [ %iv.next, %loop ], [ 0, %guardbb ]
+ %idx = getelementptr inbounds i32, i32* %a, i64 %iv
+ store i32 1, i32* %idx, align 4
+ %iv.next = add nuw nsw i64 %iv, 1
+ %exitcond = icmp eq i64 %iv, %i
+ br i1 %exitcond, label %exit, label %loop
+
+exit:
+ ret void
+}
+
+; TODO: Currently we miss getting the tightest max backedge-taken count (11).
+define void @test_multiple_var_guards_order1(i32* nocapture %a, i64 %i, i64 %N) {
+; CHECK-LABEL: @test_multiple_var_guards_order1
+; CHECK: Loop %loop: backedge-taken count is %i
+; CHECK-NEXT: Loop %loop: max backedge-taken count is -1
+; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is %i
+;
+entry:
+ %c.1 = icmp ult i64 %N, 12
+ br i1 %c.1, label %guardbb, label %exit
+
+guardbb:
+ %c.2 = icmp ult i64 %i, %N
+ br i1 %c.2, label %loop, label %exit
+
+loop:
+ %iv = phi i64 [ %iv.next, %loop ], [ 0, %guardbb ]
+ %idx = getelementptr inbounds i32, i32* %a, i64 %iv
+ store i32 1, i32* %idx, align 4
+ %iv.next = add nuw nsw i64 %iv, 1
+ %exitcond = icmp eq i64 %iv, %i
+ br i1 %exitcond, label %exit, label %loop
+
+exit:
+ ret void
+}
+
+; TODO: Currently we miss getting the tightest max backedge-taken count (11).
+define void @test_multiple_var_guards_order2(i32* nocapture %a, i64 %i, i64 %N) {
+; CHECK-LABEL: Determining loop execution counts for: @test_multiple_var_guards_order2
+; CHECK-NEXT: Loop %loop: backedge-taken count is %i
+; CHECK-NEXT: Loop %loop: max backedge-taken count is -1
+; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is %i
+;
+entry:
+ %c.1 = icmp ult i64 %i, %N
+ br i1 %c.1, label %guardbb, label %exit
+
+guardbb:
+ %c.2 = icmp ult i64 %N, 12
+ br i1 %c.2, label %loop, label %exit
+
+loop:
+ %iv = phi i64 [ %iv.next, %loop ], [ 0, %guardbb ]
+ %idx = getelementptr inbounds i32, i32* %a, i64 %iv
+ store i32 1, i32* %idx, align 4
+ %iv.next = add nuw nsw i64 %iv, 1
+ %exitcond = icmp eq i64 %iv, %i
+ br i1 %exitcond, label %exit, label %loop
+
+exit:
+ ret void
+}
+
+; The guards here reference each other in a cycle.
+define void @test_multiple_var_guards_cycle(i32* nocapture %a, i64 %i, i64 %N) {
+; CHECK-LABEL: Determining loop execution counts for: @test_multiple_var_guards_cycle
+; CHECK-NEXT: Loop %loop: backedge-taken count is %N
+; CHECK-NEXT: Loop %loop: max backedge-taken count is -1
+; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is %N
+;
+entry:
+ %c.1 = icmp ult i64 %N, %i
+ br i1 %c.1, label %guardbb, label %exit
+
+guardbb:
+ %c.2 = icmp ult i64 %i, %N
+ br i1 %c.2, label %loop, label %exit
+
+loop:
+ %iv = phi i64 [ %iv.next, %loop ], [ 0, %guardbb ]
+ %idx = getelementptr inbounds i32, i32* %a, i64 %iv
+ store i32 1, i32* %idx, align 4
+ %iv.next = add nuw nsw i64 %iv, 1
+ %exitcond = icmp eq i64 %iv, %N
+ br i1 %exitcond, label %exit, label %loop
+
+exit:
+ ret void
+}
+
; Test case for PR47247. Both the guard condition and the assume limit the
; max backedge-taken count.
define void @test_guard_and_assume(i32* nocapture readonly %data, i64 %count) {
-; CHECK-LABEL: Determining loop execution counts for: @test_guard_and_assume
-; CHECK-NEXT: Loop %loop: backedge-taken count is (-1 + %count)
+; CHECK-LABEL: @test_guard_and_assume
+; CHECK: Loop %loop: backedge-taken count is (-1 + %count)
; CHECK-NEXT: Loop %loop: max backedge-taken count is -2
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is (-1 + %count)
;
@@ -53,3 +230,68 @@ exit:
; Function Attrs: nounwind willreturn
declare void @llvm.assume(i1 noundef)
+
+define void @guard_pessimizes_analysis(i1 %c, i32 %N) {
+; CHECK-LABEL: @guard_pessimizes_analysis
+; CHECK: Loop %loop: backedge-taken count is (9 + (-1 * %init)<nsw>)<nsw>
+; CHECK-NEXT: Loop %loop: max backedge-taken count is 7
+; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is (9 + (-1 * %init)<nsw>)<nsw>
+;
+entry:
+ br i1 %c, label %bb1, label %guard
+
+bb1:
+ br label %guard
+
+guard:
+ %init = phi i32 [ 2, %entry ], [ 3, %bb1 ]
+ %c.1 = icmp ult i32 %init, %N
+ br i1 %c.1, label %loop.ph, label %exit
+
+loop.ph:
+ br label %loop
+
+loop:
+ %iv = phi i32 [ %iv.next, %loop ], [ %init, %loop.ph ]
+ %iv.next = add i32 %iv, 1
+ %exitcond = icmp eq i32 %iv.next, 10
+ br i1 %exitcond, label %exit, label %loop
+
+exit:
+ ret void
+}
+
+define void @crash(i8* %ptr) {
+; CHECK-LABEL: @crash
+; CHECK: Loop %while.body125: backedge-taken count is {(-2 + (-1 * %ptr)),+,-1}<nw><%while.cond111>
+; CHECK-NEXT: Loop %while.body125: max backedge-taken count is -1
+; CHECK-NEXT: Loop %while.body125: Predicated backedge-taken count is {(-2 + (-1 * %ptr)),+,-1}<nw><%while.cond111>
+;
+entry:
+ br label %while.body
+
+while.body:
+ br label %while.cond111
+
+while.cond111:
+ %text.addr.5 = phi i8* [ %incdec.ptr112, %while.cond111 ], [ null, %while.body ]
+ %incdec.ptr112 = getelementptr inbounds i8, i8* %text.addr.5, i64 -1
+ br i1 false, label %while.end117, label %while.cond111
+
+while.end117:
+ %cmp118 = icmp ult i8* %ptr, %incdec.ptr112
+ br i1 %cmp118, label %while.body125, label %while.cond134.preheader
+
+
+while.cond134.preheader:
+ br label %while.body
+
+while.body125:
+ %lastout.2271 = phi i8* [ %incdec.ptr126, %while.body125 ], [ %ptr, %while.end117 ]
+ %incdec.ptr126 = getelementptr inbounds i8, i8* %lastout.2271, i64 1
+ %exitcond.not = icmp eq i8* %incdec.ptr126, %incdec.ptr112
+ br i1 %exitcond.not, label %while.end129, label %while.body125
+
+while.end129: ; preds = %while.body125
+ ret void
+}
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