Find loop back edges only after empty blocks are eliminated.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61752 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng
2009-01-05 21:17:27 +00:00
parent c6c22e2542
commit 7e66c0d43a
2 changed files with 4 additions and 3 deletions
+3 -2
View File
@@ -125,12 +125,13 @@ void CodeGenPrepare::findLoopBackEdges(Function &F) {
bool CodeGenPrepare::runOnFunction(Function &F) {
bool EverMadeChange = false;
findLoopBackEdges(F);
// First pass, eliminate blocks that contain only PHI nodes and an
// unconditional branch.
EverMadeChange |= EliminateMostlyEmptyBlocks(F);
// Now find loop back edges.
findLoopBackEdges(F);
bool MadeChange = true;
while (MadeChange) {
MadeChange = false;
+1 -1
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@@ -1,4 +1,4 @@
; RUN: llvm-as < %s | llc -march=x86 | grep xor | count 1
; RUN: llvm-as < %s | llc -march=x86 | grep xor | count 2
%struct.FILE = type { i8*, i32, i32, i16, i16, %struct.__sbuf, i32, i8*, i32 (i8*)*, i32 (i8*, i8*, i32)*, i64 (i8*, i64, i32)*, i32 (i8*, i8*, i32)*, %struct.__sbuf, %struct.__sFILEX*, i32, [3 x i8], [1 x i8], %struct.__sbuf, i32, i64 }
%struct.ImgT = type { i8, i8*, i8*, %struct.FILE*, i32, i32, i32, i32, i8*, double*, float*, float*, float*, i32*, double, double, i32*, double*, i32*, i32* }