[WebAssembly] Stackify induction variable increment instructions.

This handles instructions where the defined register is also used, as in
"x = x + 1".

llvm-svn: 269830

2 files changed, 44 insertions, 14 deletions

diff --git a/llvm/test/CodeGen/WebAssembly/cfg-stackify.ll b/llvm/test/CodeGen/WebAssembly/cfg-stackify.ll
index ff945706778..cbb45611cec 100644
--- a/llvm/test/CodeGen/WebAssembly/cfg-stackify.ll
+++ b/llvm/test/CodeGen/WebAssembly/cfg-stackify.ll
@@ -15,10 +15,10 @@ declare void @something()
 
 ; CHECK-LABEL: test0:
 ; CHECK: loop
-; CHECK-NOT: br
-; CHECK: i32.add
 ; CHECK-NEXT: block
-; CHECK-NEXT: i32.lt_s
+; CHECK-NEXT: i32.const
+; CHECK-NEXT: i32.add
+; CHECK:      i32.lt_s
 ; CHECK-NEXT: br_if
 ; CHECK-NEXT: return
 ; CHECK-NEXT: .LBB0_3:
@@ -29,9 +29,9 @@ declare void @something()
 ; CHECK-NEXT: end_loop
 ; OPT-LABEL: test0:
 ; OPT: loop
-; OPT-NOT: br
-; OPT: i32.add
-; OPT-NEXT: i32.ge_s
+; OPT-NEXT: i32.const
+; OPT-NEXT: i32.add
+; OPT:      i32.ge_s
 ; OPT-NEXT: br_if
 ; OPT-NOT: br
 ; OPT: call
@@ -60,10 +60,10 @@ back:
 
 ; CHECK-LABEL: test1:
 ; CHECK: loop
-; CHECK-NOT: br
-; CHECK: i32.add
 ; CHECK-NEXT: block
-; CHECK-NEXT: i32.lt_s
+; CHECK-NEXT: i32.const
+; CHECK-NEXT: i32.add
+; CHECK:      i32.lt_s
 ; CHECK-NEXT: br_if
 ; CHECK-NEXT: return
 ; CHECK-NEXT: .LBB1_3:
@@ -74,9 +74,9 @@ back:
 ; CHECK-NEXT: end_loop
 ; OPT-LABEL: test1:
 ; OPT: loop
-; OPT-NOT: br
-; OPT: i32.add
-; OPT-NEXT: i32.ge_s
+; OPT-NEXT: i32.const
+; OPT-NEXT: i32.add
+; OPT:      i32.ge_s
 ; OPT-NEXT: br_if
 ; OPT-NOT: br
 ; OPT: call
@@ -108,16 +108,22 @@ back:
 ; CHECK: block{{$}}
 ; CHECK: br_if 0, {{[^,]+}}{{$}}
 ; CHECK: .LBB2_{{[0-9]+}}:
-; CHECK: br_if 0, ${{[0-9]+}}{{$}}
+; CHECK: loop
+; CHECK: br_if 0, $pop{{[0-9]+}}{{$}}
 ; CHECK: .LBB2_{{[0-9]+}}:
+; CHECK: end_loop
+; CHECK: end_block
 ; CHECK: return{{$}}
 ; OPT-LABEL: test2:
 ; OPT-NOT: local
 ; OPT: block{{$}}
 ; OPT: br_if 0, {{[^,]+}}{{$}}
 ; OPT: .LBB2_{{[0-9]+}}:
-; OPT: br_if 0, ${{[0-9]+}}{{$}}
+; OPT: loop
+; OPT: br_if 0, $pop{{[0-9]+}}{{$}}
 ; OPT: .LBB2_{{[0-9]+}}:
+; OPT: end_loop
+; OPT: end_block
 ; OPT: return{{$}}
 define void @test2(double* nocapture %p, i32 %n) {
 entry:
diff --git a/llvm/test/CodeGen/WebAssembly/reg-stackify.ll b/llvm/test/CodeGen/WebAssembly/reg-stackify.ll
index 8518f4c1f49..bc36357c0b9 100644
--- a/llvm/test/CodeGen/WebAssembly/reg-stackify.ll
+++ b/llvm/test/CodeGen/WebAssembly/reg-stackify.ll
@@ -400,6 +400,30 @@ define i32 @no_stackify_past_epilogue() {
   ret i32 %call
 }
 
+; Stackify a loop induction variable into a loop comparison.
+
+; CHECK_LABEL: stackify_indvar:
+; CHECK:             i32.const   $push[[L5:.+]]=, 1{{$}}
+; CHECK-NEXT:        i32.add     $push[[L4:.+]]=, $[[R0:.+]], $pop[[L5]]{{$}}
+; CHECK-NEXT:        tee_local   $push[[L3:.+]]=, $[[R0]]=, $pop[[L4]]{{$}}
+; CHECK-NEXT:        i32.ne      $push[[L2:.+]]=, $0, $pop[[L3]]{{$}}
+define void @stackify_indvar(i32 %tmp, i32* %v) #0 {
+bb:
+  br label %bb3
+
+bb3:                                              ; preds = %bb3, %bb2
+  %tmp4 = phi i32 [ %tmp7, %bb3 ], [ 0, %bb ]
+  %tmp5 = load volatile i32, i32* %v, align 4
+  %tmp6 = add nsw i32 %tmp5, %tmp4
+  store volatile i32 %tmp6, i32* %v, align 4
+  %tmp7 = add nuw nsw i32 %tmp4, 1
+  %tmp8 = icmp eq i32 %tmp7, %tmp
+  br i1 %tmp8, label %bb10, label %bb3
+
+bb10:                                             ; preds = %bb9, %bb
+  ret void
+}
+
 !llvm.module.flags = !{!0}
 !llvm.dbg.cu = !{!1}