[llvm] r261190 - [WebAssembly] Don't use setRequiresStructuredCFG(true).
Dan Gohman via llvm-commits
llvm-commits at lists.llvm.org
Wed Feb 17 22:32:54 PST 2016
Author: djg
Date: Thu Feb 18 00:32:53 2016
New Revision: 261190
URL: http://llvm.org/viewvc/llvm-project?rev=261190&view=rev
Log:
[WebAssembly] Don't use setRequiresStructuredCFG(true).
While we still do want reducible control flow, the RequiresStructuredCFG
flag imposes more strict structure constraints than WebAssembly wants.
Unsetting this flag enables critical edge splitting and tail merging.
Also, disable TailDuplication explicitly, as it doesn't support virtual
registers, and was previously only disabled by the RequiresStructuredCFG
flag.
Modified:
llvm/trunk/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
llvm/trunk/test/CodeGen/WebAssembly/cfg-stackify.ll
Modified: llvm/trunk/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp?rev=261190&r1=261189&r2=261190&view=diff
==============================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp (original)
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp Thu Feb 18 00:32:53 2016
@@ -58,9 +58,9 @@ WebAssemblyTargetMachine::WebAssemblyTar
initAsmInfo();
- // We need a reducible CFG, so disable some optimizations which tend to
- // introduce irreducibility.
- setRequiresStructuredCFG(true);
+ // Note that we don't use setRequiresStructuredCFG(true). It disables
+ // optimizations than we're ok with, and want, such as critical edge
+ // splitting and tail merging.
}
WebAssemblyTargetMachine::~WebAssemblyTargetMachine() {}
@@ -184,6 +184,7 @@ void WebAssemblyPassConfig::addPostRegAl
disablePass(&PrologEpilogCodeInserterID);
// Fails with: should be run after register allocation.
disablePass(&MachineCopyPropagationID);
+ disablePass(&TailDuplicateID);
if (getOptLevel() != CodeGenOpt::None) {
// Mark registers as representing wasm's expression stack.
Modified: llvm/trunk/test/CodeGen/WebAssembly/cfg-stackify.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WebAssembly/cfg-stackify.ll?rev=261190&r1=261189&r2=261190&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/cfg-stackify.ll (original)
+++ llvm/trunk/test/CodeGen/WebAssembly/cfg-stackify.ll Thu Feb 18 00:32:53 2016
@@ -459,9 +459,7 @@ exit:
; OPT-LABEL: test3:
; OPT: block
; OPT: br_if
-; OPT-NEXT: return
-; OPT-NEXT: .LBB{{[0-9]+}}_{{[0-9]+}}:
-; OPT-NEXT: end_block
+; OPT: .LBB{{[0-9]+}}_{{[0-9]+}}:
; OPT-NEXT: loop
; OPT-NEXT: block
; OPT-NEXT: block
@@ -513,44 +511,35 @@ if.end:
; CHECK: block{{$}}
; CHECK-NEXT: block{{$}}
; CHECK: br_if 0, $pop{{[0-9]+}}{{$}}
-; CHECK-NEXT: block{{$}}
-; CHECK: br_if 0, $pop{{[0-9]+}}{{$}}
-; CHECK: br_if 2, $pop{{[0-9]+}}{{$}}
+; CHECK: br_if 1, $pop{{[0-9]+}}{{$}}
+; CHECK: br 1{{$}}
; CHECK-NEXT: .LBB13_3:
; CHECK-NEXT: end_block{{$}}
-; CHECK-NEXT: return{{$}}
-; CHECK-NEXT: .LBB13_4:
-; CHECK-NEXT: end_block{{$}}
; CHECK-NEXT: block{{$}}
-; CHECK: br_if 0, $pop{{[0-9]+}}{{$}}
-; CHECK: br_if 1, $pop{{[0-9]+}}{{$}}
-; CHECK-NEXT: return{{$}}
-; CHECK-NEXT: .LBB13_7:
+; CHECK: br_if 0, $pop{{[0-9]+}}{{$}}
+; CHECK: br_if 1, $pop{{[0-9]+}}{{$}}
+; CHECK-NEXT: .LBB13_5:
; CHECK-NEXT: end_block{{$}}
; CHECK-NEXT: return{{$}}
-; CHECK-NEXT: .LBB13_8:
+; CHECK-NEXT: .LBB13_6:
; CHECK-NEXT: end_block{{$}}
; CHECK-NEXT: return{{$}}
; OPT-LABEL: test4:
; OPT-NEXT: .param i32{{$}}
; OPT: block{{$}}
; OPT-NEXT: block{{$}}
-; OPT-NEXT: block{{$}}
-; OPT: br_if 0, $pop{{[0-9]+}}{{$}}
-; OPT-NEXT: block{{$}}
; OPT: br_if 0, $pop{{[0-9]+}}{{$}}
-; OPT: br_if 2, $pop{{[0-9]+}}{{$}}
+; OPT: br_if 1, $pop{{[0-9]+}}{{$}}
+; OPT: br 1{{$}}
; OPT-NEXT: .LBB13_3:
; OPT-NEXT: end_block{{$}}
-; OPT-NEXT: return{{$}}
-; OPT-NEXT: .LBB13_4:
-; OPT: br_if 1, $pop{{[0-9]+}}{{$}}
+; OPT-NEXT: block{{$}}
; OPT: br_if 0, $pop{{[0-9]+}}{{$}}
-; OPT-NEXT: return{{$}}
-; OPT-NEXT: .LBB13_7:
+; OPT: br_if 1, $pop{{[0-9]+}}{{$}}
+; OPT-NEXT: .LBB13_5:
; OPT-NEXT: end_block{{$}}
; OPT-NEXT: return{{$}}
-; OPT-NEXT: .LBB13_8:
+; OPT-NEXT: .LBB13_6:
; OPT-NEXT: end_block{{$}}
; OPT-NEXT: return{{$}}
define void @test4(i32 %t) {
@@ -826,13 +815,13 @@ bb3:
; CHECK-NOT: block
; CHECK: br_if 0, {{[^,]+}}{{$}}
; CHECK-NOT: block
-; CHECK: br_if 1, {{[^,]+}}{{$}}
-; CHECK-NEXT: br 3{{$}}
+; CHECK: br_if 3, {{[^,]+}}{{$}}
+; CHECK-NEXT: br 1{{$}}
; CHECK-NEXT: .LBB18_4:
; CHECK-NEXT: end_block{{$}}
; CHECK-NOT: block
-; CHECK: br_if 0, {{[^,]+}}{{$}}
-; CHECK-NEXT: br 2{{$}}
+; CHECK: br_if 2, {{[^,]+}}{{$}}
+; CHECK-NEXT: br 0{{$}}
; CHECK-NEXT: .LBB18_5:
; CHECK-NOT: block
; CHECK: return{{$}}
@@ -1267,34 +1256,36 @@ bb50:
; CHECK: block
; CHECK-NEXT: block
; CHECK: br_if 0, $pop{{.*}}{{$}}
-; CHECK-NEXT: .LBB24_1:
+; CHECK: .LBB24_2:
; CHECK-NEXT: block{{$}}
; CHECK-NEXT: loop{{$}}
; CHECK: br_if 1, $pop{{.*}}{{$}}
-; CHECK: br_if 2, $pop{{.*}}{{$}}
-; CHECK-NEXT: br 0{{$}}
-; CHECK-NEXT: .LBB24_3:
+; CHECK: br_if 0, ${{.*}}{{$}}
+; CHECK-NEXT: br 2{{$}}
+; CHECK-NEXT: .LBB24_4:
; CHECK-NEXT: end_loop{{$}}
-; CHECK: .LBB24_4:
+; CHECK: .LBB24_5:
; CHECK-NEXT: end_block{{$}}
; CHECK: br_if 1, $pop{{.*}}{{$}}
; CHECK: return{{$}}
-; CHECK: .LBB24_6:
-; CHECK-NEXT: end_block{{$}}
-; CHECK: return{{$}}
; CHECK: .LBB24_7:
; CHECK-NEXT: end_block{{$}}
+; CHECK: .LBB24_8:
+; CHECK-NEXT: end_block{{$}}
; CHECK-NEXT: return{{$}}
; OPT-LABEL: test15:
; OPT: block
+; OPT: block
; OPT-NEXT: i32.const $push
; OPT-NEXT: i32.const $push
; OPT-NEXT: i32.eq $push{{.*}}=, $pop{{.*}}, $pop{{.*}}{{$}}
; OPT-NEXT: br_if 0, $pop{{.*}}{{$}}
; OPT-NEXT: call test15_callee1 at FUNCTION{{$}}
-; OPT-NEXT: return{{$}}
+; OPT-NEXT: br 1{{$}}
; OPT-NEXT: .LBB24_2:
; OPT-NEXT: end_block
+; OPT-NEXT: i32.const
+; OPT-NEXT: .LBB24_3:
; OPT-NEXT: block
; OPT-NEXT: loop
%0 = type { i8, i32 }
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