[llvm] a754dc2 - [Test] Two more interesting test cases & their codegen counterparts

Max Kazantsev via llvm-commits llvm-commits at lists.llvm.org
Fri Feb 26 02:26:45 PST 2021


Author: Max Kazantsev
Date: 2021-02-26T17:23:12+07:00
New Revision: a754dc235834fd4e0c63a0a35933e001e17b3921

URL: https://github.com/llvm/llvm-project/commit/a754dc235834fd4e0c63a0a35933e001e17b3921
DIFF: https://github.com/llvm/llvm-project/commit/a754dc235834fd4e0c63a0a35933e001e17b3921.diff

LOG: [Test] Two more interesting test cases & their codegen counterparts

Added: 
    llvm/test/CodeGen/X86/overflowing-iv-codegen.ll

Modified: 
    llvm/test/CodeGen/X86/overflowing-iv.ll

Removed: 
    


################################################################################
diff  --git a/llvm/test/CodeGen/X86/overflowing-iv-codegen.ll b/llvm/test/CodeGen/X86/overflowing-iv-codegen.ll
new file mode 100644
index 000000000000..08ee932bdba1
--- /dev/null
+++ b/llvm/test/CodeGen/X86/overflowing-iv-codegen.ll
@@ -0,0 +1,215 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-linux | FileCheck %s
+
+; No overflow flags, same type width.
+define i32 @test_01(i32* %p, i64 %len, i32 %x) {
+; CHECK-LABEL: test_01:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    addq $-4, %rdi
+; CHECK-NEXT:    .p2align 4, 0x90
+; CHECK-NEXT:  .LBB0_1: # %loop
+; CHECK-NEXT:    # =>This Inner Loop Header: Depth=1
+; CHECK-NEXT:    subq $1, %rsi
+; CHECK-NEXT:    jb .LBB0_4
+; CHECK-NEXT:  # %bb.2: # %backedge
+; CHECK-NEXT:    # in Loop: Header=BB0_1 Depth=1
+; CHECK-NEXT:    cmpl %edx, (%rdi)
+; CHECK-NEXT:    leaq 4(%rdi), %rdi
+; CHECK-NEXT:    jne .LBB0_1
+; CHECK-NEXT:  # %bb.3: # %failure
+; CHECK-NEXT:  .LBB0_4: # %exit
+; CHECK-NEXT:    movl $-1, %eax
+; CHECK-NEXT:    retq
+entry:
+  %scevgep = getelementptr i32, i32* %p, i64 -1
+  br label %loop
+
+loop:                                             ; preds = %backedge, %entry
+  %iv = phi i64 [ %iv.next, %backedge ], [ 0, %entry ]
+  %iv.next = add i64 %iv, 1
+  %cond_1 = icmp eq i64 %iv, %len
+  br i1 %cond_1, label %exit, label %backedge
+
+backedge:                                         ; preds = %loop
+  %scevgep1 = getelementptr i32, i32* %scevgep, i64 %iv
+  %loaded = load atomic i32, i32* %scevgep1 unordered, align 4
+  %cond_2 = icmp eq i32 %loaded, %x
+  br i1 %cond_2, label %failure, label %loop
+
+exit:                                             ; preds = %loop
+  ret i32 -1
+
+failure:                                          ; preds = %backedge
+  unreachable
+}
+
+; nsw flag, same type width.
+define i32 @test_02(i32* %p, i64 %len, i32 %x) {
+; CHECK-LABEL: test_02:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    addq $-4, %rdi
+; CHECK-NEXT:    .p2align 4, 0x90
+; CHECK-NEXT:  .LBB1_1: # %loop
+; CHECK-NEXT:    # =>This Inner Loop Header: Depth=1
+; CHECK-NEXT:    subq $1, %rsi
+; CHECK-NEXT:    jb .LBB1_4
+; CHECK-NEXT:  # %bb.2: # %backedge
+; CHECK-NEXT:    # in Loop: Header=BB1_1 Depth=1
+; CHECK-NEXT:    cmpl %edx, (%rdi)
+; CHECK-NEXT:    leaq 4(%rdi), %rdi
+; CHECK-NEXT:    jne .LBB1_1
+; CHECK-NEXT:  # %bb.3: # %failure
+; CHECK-NEXT:  .LBB1_4: # %exit
+; CHECK-NEXT:    movl $-1, %eax
+; CHECK-NEXT:    retq
+entry:
+  %scevgep = getelementptr i32, i32* %p, i64 -1
+  br label %loop
+
+loop:                                             ; preds = %backedge, %entry
+  %iv = phi i64 [ %iv.next, %backedge ], [ 0, %entry ]
+  %iv.next = add nsw i64 %iv, 1
+  %cond_1 = icmp eq i64 %iv, %len
+  br i1 %cond_1, label %exit, label %backedge
+
+backedge:                                         ; preds = %loop
+  %scevgep1 = getelementptr i32, i32* %scevgep, i64 %iv
+  %loaded = load atomic i32, i32* %scevgep1 unordered, align 4
+  %cond_2 = icmp eq i32 %loaded, %x
+  br i1 %cond_2, label %failure, label %loop
+
+exit:                                             ; preds = %loop
+  ret i32 -1
+
+failure:                                          ; preds = %backedge
+  unreachable
+}
+
+; nsw flag, optimization is possible because memory instruction is dominated by loop-exiting check against iv.next.
+define i32 @test_02_nopoison(i32* %p, i64 %len, i32 %x) {
+; CHECK-LABEL: test_02_nopoison:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    addq $-4, %rdi
+; CHECK-NEXT:    .p2align 4, 0x90
+; CHECK-NEXT:  .LBB2_1: # %loop
+; CHECK-NEXT:    # =>This Inner Loop Header: Depth=1
+; CHECK-NEXT:    subq $1, %rsi
+; CHECK-NEXT:    jb .LBB2_4
+; CHECK-NEXT:  # %bb.2: # %backedge
+; CHECK-NEXT:    # in Loop: Header=BB2_1 Depth=1
+; CHECK-NEXT:    cmpl %edx, (%rdi)
+; CHECK-NEXT:    leaq 4(%rdi), %rdi
+; CHECK-NEXT:    jne .LBB2_1
+; CHECK-NEXT:  # %bb.3: # %failure
+; CHECK-NEXT:  .LBB2_4: # %exit
+; CHECK-NEXT:    movl $-1, %eax
+; CHECK-NEXT:    retq
+entry:
+  %len.plus.1 = add i64 %len, 1
+  %scevgep = getelementptr i32, i32* %p, i64 -1
+  br label %loop
+
+loop:                                             ; preds = %backedge, %entry
+  %iv = phi i64 [ %iv.next, %backedge ], [ 0, %entry ]
+  %iv.next = add nsw i64 %iv, 1
+  %cond_1 = icmp eq i64 %iv.next, %len.plus.1
+  br i1 %cond_1, label %exit, label %backedge
+
+backedge:                                         ; preds = %loop
+  %scevgep1 = getelementptr i32, i32* %scevgep, i64 %iv
+  %loaded = load atomic i32, i32* %scevgep1 unordered, align 4
+  %cond_2 = icmp eq i32 %loaded, %x
+  br i1 %cond_2, label %failure, label %loop
+
+exit:                                             ; preds = %loop
+  ret i32 -1
+
+failure:                                          ; preds = %backedge
+  unreachable
+}
+
+
+; nuw flag, same type width.
+define i32 @test_03(i32* %p, i64 %len, i32 %x) {
+; CHECK-LABEL: test_03:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    addq $-4, %rdi
+; CHECK-NEXT:    .p2align 4, 0x90
+; CHECK-NEXT:  .LBB3_1: # %loop
+; CHECK-NEXT:    # =>This Inner Loop Header: Depth=1
+; CHECK-NEXT:    subq $1, %rsi
+; CHECK-NEXT:    jb .LBB3_4
+; CHECK-NEXT:  # %bb.2: # %backedge
+; CHECK-NEXT:    # in Loop: Header=BB3_1 Depth=1
+; CHECK-NEXT:    cmpl %edx, (%rdi)
+; CHECK-NEXT:    leaq 4(%rdi), %rdi
+; CHECK-NEXT:    jne .LBB3_1
+; CHECK-NEXT:  # %bb.3: # %failure
+; CHECK-NEXT:  .LBB3_4: # %exit
+; CHECK-NEXT:    movl $-1, %eax
+; CHECK-NEXT:    retq
+entry:
+  %scevgep = getelementptr i32, i32* %p, i64 -1
+  br label %loop
+
+loop:                                             ; preds = %backedge, %entry
+  %iv = phi i64 [ %iv.next, %backedge ], [ 0, %entry ]
+  %iv.next = add nuw i64 %iv, 1
+  %cond_1 = icmp eq i64 %iv, %len
+  br i1 %cond_1, label %exit, label %backedge
+
+backedge:                                         ; preds = %loop
+  %scevgep1 = getelementptr i32, i32* %scevgep, i64 %iv
+  %loaded = load atomic i32, i32* %scevgep1 unordered, align 4
+  %cond_2 = icmp eq i32 %loaded, %x
+  br i1 %cond_2, label %failure, label %loop
+
+exit:                                             ; preds = %loop
+  ret i32 -1
+
+failure:                                          ; preds = %backedge
+  unreachable
+}
+
+; nuw flag, optimization is possible because memory instruction is dominated by loop-exiting check against iv.next.
+define i32 @test_03_nopoison(i32* %p, i64 %len, i32 %x) {
+; CHECK-LABEL: test_03_nopoison:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    addq $-4, %rdi
+; CHECK-NEXT:    .p2align 4, 0x90
+; CHECK-NEXT:  .LBB4_1: # %loop
+; CHECK-NEXT:    # =>This Inner Loop Header: Depth=1
+; CHECK-NEXT:    subq $1, %rsi
+; CHECK-NEXT:    jb .LBB4_4
+; CHECK-NEXT:  # %bb.2: # %backedge
+; CHECK-NEXT:    # in Loop: Header=BB4_1 Depth=1
+; CHECK-NEXT:    cmpl %edx, (%rdi)
+; CHECK-NEXT:    leaq 4(%rdi), %rdi
+; CHECK-NEXT:    jne .LBB4_1
+; CHECK-NEXT:  # %bb.3: # %failure
+; CHECK-NEXT:  .LBB4_4: # %exit
+; CHECK-NEXT:    movl $-1, %eax
+; CHECK-NEXT:    retq
+entry:
+  %len.plus.1 = add i64 %len, 1
+  %scevgep = getelementptr i32, i32* %p, i64 -1
+  br label %loop
+
+loop:                                             ; preds = %backedge, %entry
+  %iv = phi i64 [ %iv.next, %backedge ], [ 0, %entry ]
+  %iv.next = add nuw i64 %iv, 1
+  %cond_1 = icmp eq i64 %iv.next, %len.plus.1
+  br i1 %cond_1, label %exit, label %backedge
+
+backedge:                                         ; preds = %loop
+  %scevgep1 = getelementptr i32, i32* %scevgep, i64 %iv
+  %loaded = load atomic i32, i32* %scevgep1 unordered, align 4
+  %cond_2 = icmp eq i32 %loaded, %x
+  br i1 %cond_2, label %failure, label %loop
+
+exit:                                             ; preds = %loop
+  ret i32 -1
+
+failure:                                          ; preds = %backedge
+  unreachable
+}

diff  --git a/llvm/test/CodeGen/X86/overflowing-iv.ll b/llvm/test/CodeGen/X86/overflowing-iv.ll
index 230d9e84a594..1d5f3c2034b3 100644
--- a/llvm/test/CodeGen/X86/overflowing-iv.ll
+++ b/llvm/test/CodeGen/X86/overflowing-iv.ll
@@ -95,6 +95,56 @@ failure:                                          ; preds = %backedge
   unreachable
 }
 
+; nsw flag, optimization is possible because memory instruction is dominated by loop-exiting check against iv.next.
+define i32 @test_02_nopoison(i32* %p, i64 %len, i32 %x) {
+; CHECK-LABEL: @test_02_nopoison(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[LEN_PLUS_1:%.*]] = add i64 [[LEN:%.*]], 1
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], [[BACKEDGE:%.*]] ], [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add nsw i64 [[IV]], 1
+; CHECK-NEXT:    [[COND_1:%.*]] = icmp eq i64 [[IV_NEXT]], [[LEN_PLUS_1]]
+; CHECK-NEXT:    br i1 [[COND_1]], label [[EXIT:%.*]], label [[BACKEDGE]]
+; CHECK:       backedge:
+; CHECK-NEXT:    [[SUNKADDR:%.*]] = mul i64 [[IV]], 4
+; CHECK-NEXT:    [[TMP0:%.*]] = bitcast i32* [[P:%.*]] to i8*
+; CHECK-NEXT:    [[SUNKADDR1:%.*]] = getelementptr i8, i8* [[TMP0]], i64 [[SUNKADDR]]
+; CHECK-NEXT:    [[SUNKADDR2:%.*]] = getelementptr i8, i8* [[SUNKADDR1]], i64 -4
+; CHECK-NEXT:    [[TMP1:%.*]] = bitcast i8* [[SUNKADDR2]] to i32*
+; CHECK-NEXT:    [[LOADED:%.*]] = load atomic i32, i32* [[TMP1]] unordered, align 4
+; CHECK-NEXT:    [[COND_2:%.*]] = icmp eq i32 [[LOADED]], [[X:%.*]]
+; CHECK-NEXT:    br i1 [[COND_2]], label [[FAILURE:%.*]], label [[LOOP]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret i32 -1
+; CHECK:       failure:
+; CHECK-NEXT:    unreachable
+;
+entry:
+  %len.plus.1 = add i64 %len, 1
+  %scevgep = getelementptr i32, i32* %p, i64 -1
+  br label %loop
+
+loop:                                             ; preds = %backedge, %entry
+  %iv = phi i64 [ %iv.next, %backedge ], [ 0, %entry ]
+  %iv.next = add nsw i64 %iv, 1
+  %cond_1 = icmp eq i64 %iv.next, %len.plus.1
+  br i1 %cond_1, label %exit, label %backedge
+
+backedge:                                         ; preds = %loop
+  %scevgep1 = getelementptr i32, i32* %scevgep, i64 %iv
+  %loaded = load atomic i32, i32* %scevgep1 unordered, align 4
+  %cond_2 = icmp eq i32 %loaded, %x
+  br i1 %cond_2, label %failure, label %loop
+
+exit:                                             ; preds = %loop
+  ret i32 -1
+
+failure:                                          ; preds = %backedge
+  unreachable
+}
+
+
 ; nuw flag, same type width.
 define i32 @test_03(i32* %p, i64 %len, i32 %x) {
 ; CHECK-LABEL: @test_03(
@@ -141,3 +191,52 @@ exit:                                             ; preds = %loop
 failure:                                          ; preds = %backedge
   unreachable
 }
+
+; nuw flag, optimization is possible because memory instruction is dominated by loop-exiting check against iv.next.
+define i32 @test_03_nopoison(i32* %p, i64 %len, i32 %x) {
+; CHECK-LABEL: @test_03_nopoison(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[LEN_PLUS_1:%.*]] = add i64 [[LEN:%.*]], 1
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], [[BACKEDGE:%.*]] ], [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[IV_NEXT]] = add nuw i64 [[IV]], 1
+; CHECK-NEXT:    [[COND_1:%.*]] = icmp eq i64 [[IV_NEXT]], [[LEN_PLUS_1]]
+; CHECK-NEXT:    br i1 [[COND_1]], label [[EXIT:%.*]], label [[BACKEDGE]]
+; CHECK:       backedge:
+; CHECK-NEXT:    [[SUNKADDR:%.*]] = mul i64 [[IV]], 4
+; CHECK-NEXT:    [[TMP0:%.*]] = bitcast i32* [[P:%.*]] to i8*
+; CHECK-NEXT:    [[SUNKADDR1:%.*]] = getelementptr i8, i8* [[TMP0]], i64 [[SUNKADDR]]
+; CHECK-NEXT:    [[SUNKADDR2:%.*]] = getelementptr i8, i8* [[SUNKADDR1]], i64 -4
+; CHECK-NEXT:    [[TMP1:%.*]] = bitcast i8* [[SUNKADDR2]] to i32*
+; CHECK-NEXT:    [[LOADED:%.*]] = load atomic i32, i32* [[TMP1]] unordered, align 4
+; CHECK-NEXT:    [[COND_2:%.*]] = icmp eq i32 [[LOADED]], [[X:%.*]]
+; CHECK-NEXT:    br i1 [[COND_2]], label [[FAILURE:%.*]], label [[LOOP]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret i32 -1
+; CHECK:       failure:
+; CHECK-NEXT:    unreachable
+;
+entry:
+  %len.plus.1 = add i64 %len, 1
+  %scevgep = getelementptr i32, i32* %p, i64 -1
+  br label %loop
+
+loop:                                             ; preds = %backedge, %entry
+  %iv = phi i64 [ %iv.next, %backedge ], [ 0, %entry ]
+  %iv.next = add nuw i64 %iv, 1
+  %cond_1 = icmp eq i64 %iv.next, %len.plus.1
+  br i1 %cond_1, label %exit, label %backedge
+
+backedge:                                         ; preds = %loop
+  %scevgep1 = getelementptr i32, i32* %scevgep, i64 %iv
+  %loaded = load atomic i32, i32* %scevgep1 unordered, align 4
+  %cond_2 = icmp eq i32 %loaded, %x
+  br i1 %cond_2, label %failure, label %loop
+
+exit:                                             ; preds = %loop
+  ret i32 -1
+
+failure:                                          ; preds = %backedge
+  unreachable
+}


        


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