1 files changed, 364 insertions, 0 deletions
diff --git a/llvm/test/Transforms/DivRemPairs/div-rem-pairs.ll b/llvm/test/Transforms/DivRemPairs/div-rem-pairs.ll
new file mode 100644
index 00000000000..30f4a79a9cd
--- /dev/null
+++ b/llvm/test/Transforms/DivRemPairs/div-rem-pairs.ll
@@ -0,0 +1,364 @@
+; RUN: opt < %s -div-rem-pairs -S -mtriple=x86_64-unknown-unknown    | FileCheck %s --check-prefix=ALL --check-prefix=X86
+; RUN: opt < %s -div-rem-pairs -S -mtriple=powerpc64-unknown-unknown | FileCheck %s --check-prefix=ALL --check-prefix=PPC
+
+declare void @foo(i32, i32)
+
+define void @decompose_illegal_srem_same_block(i32 %a, i32 %b) {
+; X86-LABEL: @decompose_illegal_srem_same_block(
+; X86-NEXT:    [[REM:%.*]] = srem i32 %a, %b
+; X86-NEXT:    [[DIV:%.*]] = sdiv i32 %a, %b
+; X86-NEXT:    call void @foo(i32 [[REM]], i32 [[DIV]])
+; X86-NEXT:    ret void
+;
+; PPC-LABEL: @decompose_illegal_srem_same_block(
+; PPC-NEXT:    [[DIV:%.*]] = sdiv i32 %a, %b
+; PPC-NEXT:    [[TMP1:%.*]] = mul i32 [[DIV]], %b
+; PPC-NEXT:    [[TMP2:%.*]] = sub i32 %a, [[TMP1]]
+; PPC-NEXT:    call void @foo(i32 [[TMP2]], i32 [[DIV]])
+; PPC-NEXT:    ret void
+;
+  %rem = srem i32 %a, %b
+  %div = sdiv i32 %a, %b
+  call void @foo(i32 %rem, i32 %div)
+  ret void
+}
+
+define void @decompose_illegal_urem_same_block(i32 %a, i32 %b) {
+; X86-LABEL: @decompose_illegal_urem_same_block(
+; X86-NEXT:    [[DIV:%.*]] = udiv i32 %a, %b
+; X86-NEXT:    [[REM:%.*]] = urem i32 %a, %b
+; X86-NEXT:    call void @foo(i32 [[REM]], i32 [[DIV]])
+; X86-NEXT:    ret void
+;
+; PPC-LABEL: @decompose_illegal_urem_same_block(
+; PPC-NEXT:    [[DIV:%.*]] = udiv i32 %a, %b
+; PPC-NEXT:    [[TMP1:%.*]] = mul i32 [[DIV]], %b
+; PPC-NEXT:    [[TMP2:%.*]] = sub i32 %a, [[TMP1]]
+; PPC-NEXT:    call void @foo(i32 [[TMP2]], i32 [[DIV]])
+; PPC-NEXT:    ret void
+;
+  %div = udiv i32 %a, %b
+  %rem = urem i32 %a, %b
+  call void @foo(i32 %rem, i32 %div)
+  ret void
+}
+
+; Hoist and optionally decompose the sdiv because it's safe and free.
+; PR31028 - https://bugs.llvm.org/show_bug.cgi?id=31028
+
+define i32 @hoist_sdiv(i32 %a, i32 %b) {
+; X86-LABEL: @hoist_sdiv(
+; X86-NEXT:  entry:
+; X86-NEXT:    [[REM:%.*]] = srem i32 %a, %b
+; X86-NEXT:    [[DIV:%.*]] = sdiv i32 %a, %b
+; X86-NEXT:    [[CMP:%.*]] = icmp eq i32 [[REM]], 42
+; X86-NEXT:    br i1 [[CMP]], label %if, label %end
+; X86:       if:
+; X86-NEXT:    br label %end
+; X86:       end:
+; X86-NEXT:    [[RET:%.*]] = phi i32 [ [[DIV]], %if ], [ 3, %entry ]
+; X86-NEXT:    ret i32 [[RET]]
+;
+; PPC-LABEL: @hoist_sdiv(
+; PPC-NEXT:  entry:
+; PPC-NEXT:    [[DIV:%.*]] = sdiv i32 %a, %b
+; PPC-NEXT:    [[TMP0:%.*]] = mul i32 [[DIV]], %b
+; PPC-NEXT:    [[TMP1:%.*]] = sub i32 %a, [[TMP0]]
+; PPC-NEXT:    [[CMP:%.*]] = icmp eq i32 [[TMP1]], 42
+; PPC-NEXT:    br i1 [[CMP]], label %if, label %end
+; PPC:       if:
+; PPC-NEXT:    br label %end
+; PPC:       end:
+; PPC-NEXT:    [[RET:%.*]] = phi i32 [ [[DIV]], %if ], [ 3, %entry ]
+; PPC-NEXT:    ret i32 [[RET]]
+;
+entry:
+  %rem = srem i32 %a, %b
+  %cmp = icmp eq i32 %rem, 42
+  br i1 %cmp, label %if, label %end
+
+if:
+  %div = sdiv i32 %a, %b
+  br label %end
+
+end:
+  %ret = phi i32 [ %div, %if ], [ 3, %entry ]
+  ret i32 %ret
+}
+
+; Hoist and optionally decompose the udiv because it's safe and free.
+
+define i64 @hoist_udiv(i64 %a, i64 %b) {
+; X86-LABEL: @hoist_udiv(
+; X86-NEXT:  entry:
+; X86-NEXT:    [[REM:%.*]] = urem i64 %a, %b
+; X86-NEXT:    [[DIV:%.*]] = udiv i64 %a, %b
+; X86-NEXT:    [[CMP:%.*]] = icmp eq i64 [[REM]], 42
+; X86-NEXT:    br i1 [[CMP]], label %if, label %end
+; X86:       if:
+; X86-NEXT:    br label %end
+; X86:       end:
+; X86-NEXT:    [[RET:%.*]] = phi i64 [ [[DIV]], %if ], [ 3, %entry ]
+; X86-NEXT:    ret i64 [[RET]]
+;
+; PPC-LABEL: @hoist_udiv(
+; PPC-NEXT:  entry:
+; PPC-NEXT:    [[DIV:%.*]] = udiv i64 %a, %b
+; PPC-NEXT:    [[TMP0:%.*]] = mul i64 [[DIV]], %b
+; PPC-NEXT:    [[TMP1:%.*]] = sub i64 %a, [[TMP0]]
+; PPC-NEXT:    [[CMP:%.*]] = icmp eq i64 [[TMP1]], 42
+; PPC-NEXT:    br i1 [[CMP]], label %if, label %end
+; PPC:       if:
+; PPC-NEXT:    br label %end
+; PPC:       end:
+; PPC-NEXT:    [[RET:%.*]] = phi i64 [ [[DIV]], %if ], [ 3, %entry ]
+; PPC-NEXT:    ret i64 [[RET]]
+;
+entry:
+  %rem = urem i64 %a, %b
+  %cmp = icmp eq i64 %rem, 42
+  br i1 %cmp, label %if, label %end
+
+if:
+  %div = udiv i64 %a, %b
+  br label %end
+
+end:
+  %ret = phi i64 [ %div, %if ], [ 3, %entry ]
+  ret i64 %ret
+}
+
+; Hoist the srem if it's safe and free, otherwise decompose it.
+
+define i16 @hoist_srem(i16 %a, i16 %b) {
+; X86-LABEL: @hoist_srem(
+; X86-NEXT:  entry:
+; X86-NEXT:    [[DIV:%.*]] = sdiv i16 %a, %b
+; X86-NEXT:    [[REM:%.*]] = srem i16 %a, %b
+; X86-NEXT:    [[CMP:%.*]] = icmp eq i16 [[DIV]], 42
+; X86-NEXT:    br i1 [[CMP]], label %if, label %end
+; X86:       if:
+; X86-NEXT:    br label %end
+; X86:       end:
+; X86-NEXT:    [[RET:%.*]] = phi i16 [ [[REM]], %if ], [ 3, %entry ]
+; X86-NEXT:    ret i16 [[RET]]
+;
+; PPC-LABEL: @hoist_srem(
+; PPC-NEXT:  entry:
+; PPC-NEXT:    [[DIV:%.*]] = sdiv i16 %a, %b
+; PPC-NEXT:    [[CMP:%.*]] = icmp eq i16 [[DIV]], 42
+; PPC-NEXT:    br i1 [[CMP]], label %if, label %end
+; PPC:       if:
+; PPC-NEXT:    [[TMP0:%.*]] = mul i16 [[DIV]], %b
+; PPC-NEXT:    [[TMP1:%.*]] = sub i16 %a, [[TMP0]]
+; PPC-NEXT:    br label %end
+; PPC:       end:
+; PPC-NEXT:    [[RET:%.*]] = phi i16 [ [[TMP1]], %if ], [ 3, %entry ]
+; PPC-NEXT:    ret i16 [[RET]]
+;
+entry:
+  %div = sdiv i16 %a, %b
+  %cmp = icmp eq i16 %div, 42
+  br i1 %cmp, label %if, label %end
+
+if:
+  %rem = srem i16 %a, %b
+  br label %end
+
+end:
+  %ret = phi i16 [ %rem, %if ], [ 3, %entry ]
+  ret i16 %ret
+}
+
+; Hoist the urem if it's safe and free, otherwise decompose it.
+
+define i8 @hoist_urem(i8 %a, i8 %b) {
+; X86-LABEL: @hoist_urem(
+; X86-NEXT:  entry:
+; X86-NEXT:    [[DIV:%.*]] = udiv i8 %a, %b
+; X86-NEXT:    [[REM:%.*]] = urem i8 %a, %b
+; X86-NEXT:    [[CMP:%.*]] = icmp eq i8 [[DIV]], 42
+; X86-NEXT:    br i1 [[CMP]], label %if, label %end
+; X86:       if:
+; X86-NEXT:    br label %end
+; X86:       end:
+; X86-NEXT:    [[RET:%.*]] = phi i8 [ [[REM]], %if ], [ 3, %entry ]
+; X86-NEXT:    ret i8 [[RET]]
+;
+; PPC-LABEL: @hoist_urem(
+; PPC-NEXT:  entry:
+; PPC-NEXT:    [[DIV:%.*]] = udiv i8 %a, %b
+; PPC-NEXT:    [[CMP:%.*]] = icmp eq i8 [[DIV]], 42
+; PPC-NEXT:    br i1 [[CMP]], label %if, label %end
+; PPC:       if:
+; PPC-NEXT:    [[TMP0:%.*]] = mul i8 [[DIV]], %b
+; PPC-NEXT:    [[TMP1:%.*]] = sub i8 %a, [[TMP0]]
+; PPC-NEXT:    br label %end
+; PPC:       end:
+; PPC-NEXT:    [[RET:%.*]] = phi i8 [ [[TMP1]], %if ], [ 3, %entry ]
+; PPC-NEXT:    ret i8 [[RET]]
+;
+entry:
+  %div = udiv i8 %a, %b
+  %cmp = icmp eq i8 %div, 42
+  br i1 %cmp, label %if, label %end
+
+if:
+  %rem = urem i8 %a, %b
+  br label %end
+
+end:
+  %ret = phi i8 [ %rem, %if ], [ 3, %entry ]
+  ret i8 %ret
+}
+
+; If the ops don't match, don't do anything: signedness.
+
+define i32 @dont_hoist_udiv(i32 %a, i32 %b) {
+; ALL-LABEL: @dont_hoist_udiv(
+; ALL-NEXT:  entry:
+; ALL-NEXT:    [[REM:%.*]] = srem i32 %a, %b
+; ALL-NEXT:    [[CMP:%.*]] = icmp eq i32 [[REM]], 42
+; ALL-NEXT:    br i1 [[CMP]], label %if, label %end
+; ALL:       if:
+; ALL-NEXT:    [[DIV:%.*]] = udiv i32 %a, %b
+; ALL-NEXT:    br label %end
+; ALL:       end:
+; ALL-NEXT:    [[RET:%.*]] = phi i32 [ [[DIV]], %if ], [ 3, %entry ]
+; ALL-NEXT:    ret i32 [[RET]]
+;
+entry:
+  %rem = srem i32 %a, %b
+  %cmp = icmp eq i32 %rem, 42
+  br i1 %cmp, label %if, label %end
+
+if:
+  %div = udiv i32 %a, %b
+  br label %end
+
+end:
+  %ret = phi i32 [ %div, %if ], [ 3, %entry ]
+  ret i32 %ret
+}
+
+; If the ops don't match, don't do anything: operation.
+
+define i32 @dont_hoist_srem(i32 %a, i32 %b) {
+; ALL-LABEL: @dont_hoist_srem(
+; ALL-NEXT:  entry:
+; ALL-NEXT:    [[REM:%.*]] = urem i32 %a, %b
+; ALL-NEXT:    [[CMP:%.*]] = icmp eq i32 [[REM]], 42
+; ALL-NEXT:    br i1 [[CMP]], label %if, label %end
+; ALL:       if:
+; ALL-NEXT:    [[REM2:%.*]] = srem i32 %a, %b
+; ALL-NEXT:    br label %end
+; ALL:       end:
+; ALL-NEXT:    [[RET:%.*]] = phi i32 [ [[REM2]], %if ], [ 3, %entry ]
+; ALL-NEXT:    ret i32 [[RET]]
+;
+entry:
+  %rem = urem i32 %a, %b
+  %cmp = icmp eq i32 %rem, 42
+  br i1 %cmp, label %if, label %end
+
+if:
+  %rem2 = srem i32 %a, %b
+  br label %end
+
+end:
+  %ret = phi i32 [ %rem2, %if ], [ 3, %entry ]
+  ret i32 %ret
+}
+
+; If the ops don't match, don't do anything: operands.
+
+define i32 @dont_hoist_sdiv(i32 %a, i32 %b, i32 %c) {
+; ALL-LABEL: @dont_hoist_sdiv(
+; ALL-NEXT:  entry:
+; ALL-NEXT:    [[REM:%.*]] = srem i32 %a, %b
+; ALL-NEXT:    [[CMP:%.*]] = icmp eq i32 [[REM]], 42
+; ALL-NEXT:    br i1 [[CMP]], label %if, label %end
+; ALL:       if:
+; ALL-NEXT:    [[DIV:%.*]] = sdiv i32 %a, %c
+; ALL-NEXT:    br label %end
+; ALL:       end:
+; ALL-NEXT:    [[RET:%.*]] = phi i32 [ [[DIV]], %if ], [ 3, %entry ]
+; ALL-NEXT:    ret i32 [[RET]]
+;
+entry:
+  %rem = srem i32 %a, %b
+  %cmp = icmp eq i32 %rem, 42
+  br i1 %cmp, label %if, label %end
+
+if:
+  %div = sdiv i32 %a, %c
+  br label %end
+
+end:
+  %ret = phi i32 [ %div, %if ], [ 3, %entry ]
+  ret i32 %ret
+}
+
+; If the target doesn't have a unified div/rem op for the type, decompose rem in-place to mul+sub.
+
+define i128 @dont_hoist_urem(i128 %a, i128 %b) {
+; ALL-LABEL: @dont_hoist_urem(
+; ALL-NEXT:  entry:
+; ALL-NEXT:    [[DIV:%.*]] = udiv i128 %a, %b
+; ALL-NEXT:    [[CMP:%.*]] = icmp eq i128 [[DIV]], 42
+; ALL-NEXT:    br i1 [[CMP]], label %if, label %end
+; ALL:       if:
+; ALL-NEXT:    [[TMP0:%.*]] = mul i128 [[DIV]], %b
+; ALL-NEXT:    [[TMP1:%.*]] = sub i128 %a, [[TMP0]]
+; ALL-NEXT:    br label %end
+; ALL:       end:
+; ALL-NEXT:    [[RET:%.*]] = phi i128 [ [[TMP1]], %if ], [ 3, %entry ]
+; ALL-NEXT:    ret i128 [[RET]]
+;
+entry:
+  %div = udiv i128 %a, %b
+  %cmp = icmp eq i128 %div, 42
+  br i1 %cmp, label %if, label %end
+
+if:
+  %rem = urem i128 %a, %b
+  br label %end
+
+end:
+  %ret = phi i128 [ %rem, %if ], [ 3, %entry ]
+  ret i128 %ret
+}
+
+; We don't hoist if one op does not dominate the other,
+; but we could hoist both ops to the common predecessor block?
+
+define i32 @no_domination(i1 %cmp, i32 %a, i32 %b) {
+; ALL-LABEL: @no_domination(
+; ALL-NEXT:  entry:
+; ALL-NEXT:    br i1 %cmp, label %if, label %else
+; ALL:       if:
+; ALL-NEXT:    [[DIV:%.*]] = sdiv i32 %a, %b
+; ALL-NEXT:    br label %end
+; ALL:       else:
+; ALL-NEXT:    [[REM:%.*]] = srem i32 %a, %b
+; ALL-NEXT:    br label %end
+; ALL:       end:
+; ALL-NEXT:    [[RET:%.*]] = phi i32 [ [[DIV]], %if ], [ [[REM]], %else ]
+; ALL-NEXT:    ret i32 [[RET]]
+;
+entry:
+  br i1 %cmp, label %if, label %else
+
+if:
+  %div = sdiv i32 %a, %b
+  br label %end
+
+else:
+  %rem = srem i32 %a, %b
+  br label %end
+
+end:
+  %ret = phi i32 [ %div, %if ], [ %rem, %else ]
+  ret i32 %ret
+}
+