Congzhe Cao ce2db9005d [LoopInterchange] Fix transformation bugs in loop interchange
After loop interchange, the (old) outer loop header should not jump to
the `LoopExit`. Note that the old outer loop becomes the new inner loop
after interchange. If we branched to `LoopExit` then after interchange
we would jump directly from the (new) inner loop header to `LoopExit`
without executing the rest of outer loop.

This patch modifies adjustLoopBranches() such that the old outer
loop header (which becomes the new inner loop header) jumps to the
old inner loop latch which becomes the new outer loop latch after
interchange.

Reviewed By: bmahjour

Differential Revision: https://reviews.llvm.org/D98475
2021-04-08 14:58:13 -04:00

167 lines
8.1 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -basic-aa -loop-interchange -pass-remarks-missed='loop-interchange' -verify-loop-lcssa -S | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
; void foo(int n, int m) {
; int temp[16][16];
; int res[16][16];
; for(int i = 0; i < n; i++) {
; for(int j = 0; j < m; j++)
; res[j][i] = temp[j][i];
; }
; }
define void @lcssa_08(i32 %n, i32 %m) {
; CHECK-LABEL: @lcssa_08(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TEMP:%.*]] = alloca [16 x [16 x i32]], align 4
; CHECK-NEXT: [[RES:%.*]] = alloca [16 x [16 x i32]], align 4
; CHECK-NEXT: [[CMP24:%.*]] = icmp sgt i32 [[N:%.*]], 0
; CHECK-NEXT: br i1 [[CMP24]], label [[INNER_PREHEADER:%.*]], label [[FOR_COND_CLEANUP:%.*]]
; CHECK: outer.preheader:
; CHECK-NEXT: br label [[OUTER_HEADER:%.*]]
; CHECK: outer.header:
; CHECK-NEXT: [[INDVARS_IV27:%.*]] = phi i64 [ 0, [[OUTER_PREHEADER:%.*]] ], [ [[INDVARS_IV_NEXT28:%.*]], [[OUTER_LATCH:%.*]] ]
; CHECK-NEXT: [[CMP222:%.*]] = icmp sgt i32 [[M:%.*]], 0
; CHECK-NEXT: [[WIDE_TRIP_COUNT:%.*]] = zext i32 [[M]] to i64
; CHECK-NEXT: br i1 [[CMP222]], label [[INNER_FOR_BODY_SPLIT1:%.*]], label [[INNER_FOR_BODY_SPLIT:%.*]]
; CHECK: inner.preheader:
; CHECK-NEXT: [[WIDE_TRIP_COUNT29:%.*]] = zext i32 [[N]] to i64
; CHECK-NEXT: br label [[INNER_FOR_BODY:%.*]]
; CHECK: inner.for.body:
; CHECK-NEXT: [[INDVARS_IV:%.*]] = phi i64 [ 0, [[INNER_PREHEADER]] ], [ [[TMP1:%.*]], [[INNER_FOR_BODY_SPLIT]] ]
; CHECK-NEXT: br label [[OUTER_PREHEADER]]
; CHECK: inner.for.body.split1:
; CHECK-NEXT: [[ARRAYIDX6:%.*]] = getelementptr inbounds [16 x [16 x i32]], [16 x [16 x i32]]* [[TEMP]], i64 0, i64 [[INDVARS_IV]], i64 [[INDVARS_IV27]]
; CHECK-NEXT: [[TMP0:%.*]] = load i32, i32* [[ARRAYIDX6]], align 4
; CHECK-NEXT: [[ARRAYIDX8:%.*]] = getelementptr inbounds [16 x [16 x i32]], [16 x [16 x i32]]* [[RES]], i64 0, i64 [[INDVARS_IV]], i64 [[INDVARS_IV27]]
; CHECK-NEXT: store i32 [[TMP0]], i32* [[ARRAYIDX8]], align 4
; CHECK-NEXT: [[INDVARS_IV_NEXT:%.*]] = add nuw nsw i64 [[INDVARS_IV]], 1
; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i64 [[INDVARS_IV_NEXT]], [[WIDE_TRIP_COUNT]]
; CHECK-NEXT: br label [[INNER_CRIT_EDGE:%.*]]
; CHECK: inner.for.body.split:
; CHECK-NEXT: [[WIDE_TRIP_COUNT_LCSSA:%.*]] = phi i64 [ [[WIDE_TRIP_COUNT]], [[OUTER_LATCH]] ], [ [[WIDE_TRIP_COUNT]], [[OUTER_HEADER]] ]
; CHECK-NEXT: [[TMP1]] = add nuw nsw i64 [[INDVARS_IV]], 1
; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i64 [[TMP1]], [[WIDE_TRIP_COUNT_LCSSA]]
; CHECK-NEXT: br i1 [[TMP2]], label [[INNER_FOR_BODY]], label [[OUTER_CRIT_EDGE:%.*]]
; CHECK: inner.crit_edge:
; CHECK-NEXT: br label [[OUTER_LATCH]]
; CHECK: outer.latch:
; CHECK-NEXT: [[INDVARS_IV_NEXT28]] = add nuw nsw i64 [[INDVARS_IV27]], 1
; CHECK-NEXT: [[EXITCOND30:%.*]] = icmp ne i64 [[INDVARS_IV_NEXT28]], [[WIDE_TRIP_COUNT29]]
; CHECK-NEXT: br i1 [[EXITCOND30]], label [[OUTER_HEADER]], label [[INNER_FOR_BODY_SPLIT]]
; CHECK: outer.crit_edge:
; CHECK-NEXT: br label [[FOR_COND_CLEANUP]]
; CHECK: for.cond.cleanup:
; CHECK-NEXT: ret void
;
entry:
%temp = alloca [16 x [16 x i32]], align 4
%res = alloca [16 x [16 x i32]], align 4
%cmp24 = icmp sgt i32 %n, 0
br i1 %cmp24, label %outer.preheader, label %for.cond.cleanup
outer.preheader: ; preds = %entry
%wide.trip.count29 = zext i32 %n to i64
br label %outer.header
outer.header: ; preds = %outer.preheader, %outer.latch
%indvars.iv27 = phi i64 [ 0, %outer.preheader ], [ %indvars.iv.next28, %outer.latch ]
%cmp222 = icmp sgt i32 %m, 0
br i1 %cmp222, label %inner.preheader, label %outer.latch
inner.preheader: ; preds = %outer.header
; When inner.preheader becomes the outer preheader, do not move
; %wide.trip.count into the inner loop header lest LCSSA break
; (if %wide.trip.count gets moved, its use is now outside the inner loop).
%wide.trip.count = zext i32 %m to i64
br label %inner.for.body
inner.for.body: ; preds = %inner.preheader, %inner.for.body
%indvars.iv = phi i64 [ 0, %inner.preheader ], [ %indvars.iv.next, %inner.for.body ]
%arrayidx6 = getelementptr inbounds [16 x [16 x i32]], [16 x [16 x i32]]* %temp, i64 0, i64 %indvars.iv, i64 %indvars.iv27
%0 = load i32, i32* %arrayidx6, align 4
%arrayidx8 = getelementptr inbounds [16 x [16 x i32]], [16 x [16 x i32]]* %res, i64 0, i64 %indvars.iv, i64 %indvars.iv27
store i32 %0, i32* %arrayidx8, align 4
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%exitcond = icmp ne i64 %indvars.iv.next, %wide.trip.count
br i1 %exitcond, label %inner.for.body, label %inner.crit_edge
inner.crit_edge: ; preds = %inner.for.body
br label %outer.latch
outer.latch: ; preds = %inner.crit_edge, %outer.header
%indvars.iv.next28 = add nuw nsw i64 %indvars.iv27, 1
%exitcond30 = icmp ne i64 %indvars.iv.next28, %wide.trip.count29
br i1 %exitcond30, label %outer.header, label %outer.crit_edge
outer.crit_edge: ; preds = %outer.latch
br label %for.cond.cleanup
for.cond.cleanup: ; preds = %outer.crit_edge, %entry
ret void
}
@global = external local_unnamed_addr global [4 x [4 x [2 x i16]]] align 16
; %N.ext is defined in the outer loop header and used in the inner loop. After
; interchanging, it will be defined in the new inner loop and used in the new;
; outer latch, so we need to create a new LCSSA phi node for it.
define void @test2(i32 %N) {
; CHECK-LABEL: @test2(
; CHECK-NEXT: bb:
; CHECK-NEXT: br label [[INNER_PREHEADER:%.*]]
; CHECK: outer.header.preheader:
; CHECK-NEXT: br label [[OUTER_HEADER:%.*]]
; CHECK: outer.header:
; CHECK-NEXT: [[OUTER_IV:%.*]] = phi i64 [ [[OUTER_IV_NEXT:%.*]], [[OUTER_LATCH:%.*]] ], [ 0, [[OUTER_HEADER_PREHEADER:%.*]] ]
; CHECK-NEXT: [[N_EXT:%.*]] = sext i32 [[N:%.*]] to i64
; CHECK-NEXT: br label [[INNER_SPLIT1:%.*]]
; CHECK: inner.preheader:
; CHECK-NEXT: br label [[INNER:%.*]]
; CHECK: inner:
; CHECK-NEXT: [[INNER_IV:%.*]] = phi i64 [ [[TMP0:%.*]], [[INNER_SPLIT:%.*]] ], [ 0, [[INNER_PREHEADER]] ]
; CHECK-NEXT: br label [[OUTER_HEADER_PREHEADER]]
; CHECK: inner.split1:
; CHECK-NEXT: [[TMP8:%.*]] = getelementptr inbounds [4 x [4 x [2 x i16]]], [4 x [4 x [2 x i16]]]* @global, i64 0, i64 [[INNER_IV]], i64 [[OUTER_IV]], i64 0
; CHECK-NEXT: [[INNER_IV_NEXT:%.*]] = add nsw i64 [[INNER_IV]], 1
; CHECK-NEXT: [[C_1:%.*]] = icmp ne i64 [[INNER_IV_NEXT]], [[N_EXT]]
; CHECK-NEXT: br label [[OUTER_LATCH]]
; CHECK: inner.split:
; CHECK-NEXT: [[N_EXT_LCSSA:%.*]] = phi i64 [ [[N_EXT]], [[OUTER_LATCH]] ]
; CHECK-NEXT: [[TMP0]] = add nsw i64 [[INNER_IV]], 1
; CHECK-NEXT: [[TMP1:%.*]] = icmp ne i64 [[TMP0]], [[N_EXT_LCSSA]]
; CHECK-NEXT: br i1 [[TMP1]], label [[INNER]], label [[EXIT:%.*]]
; CHECK: outer.latch:
; CHECK-NEXT: [[OUTER_IV_NEXT]] = add nsw i64 [[OUTER_IV]], 1
; CHECK-NEXT: [[C_2:%.*]] = icmp ne i64 [[OUTER_IV]], [[N_EXT]]
; CHECK-NEXT: br i1 [[C_2]], label [[OUTER_HEADER]], label [[INNER_SPLIT]]
; CHECK: exit:
; CHECK-NEXT: ret void
;
bb:
br label %outer.header
outer.header: ; preds = %bb11, %bb2
%outer.iv = phi i64 [ 0, %bb ], [ %outer.iv.next, %outer.latch ]
%N.ext = sext i32 %N to i64
br label %inner
inner: ; preds = %bb6, %bb4
%inner.iv = phi i64 [ 0, %outer.header ], [ %inner.iv.next, %inner ]
%tmp8 = getelementptr inbounds [4 x [4 x [2 x i16]]], [4 x [4 x [2 x i16]]]* @global, i64 0, i64 %inner.iv, i64 %outer.iv, i64 0
%inner.iv.next = add nsw i64 %inner.iv, 1
%c.1 = icmp ne i64 %inner.iv.next, %N.ext
br i1 %c.1, label %inner, label %outer.latch
outer.latch: ; preds = %bb6
%outer.iv.next = add nsw i64 %outer.iv, 1
%c.2 = icmp ne i64 %outer.iv, %N.ext
br i1 %c.2 , label %outer.header, label %exit
exit: ; preds = %bb11
ret void
}