Avoid processing early clobbers twice in RegAllocFast.

Early clobbers defining a virtual register were first alocated to a physreg and
then processed as a physreg EC, spilling the virtreg.

This fixes PR7382.

llvm-svn: 105998

1 files changed, 29 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/X86/2010-06-15-FastAllocEarlyCLobber.ll b/llvm/test/CodeGen/X86/2010-06-15-FastAllocEarlyCLobber.ll
new file mode 100644
index 00000000000..4639866afc5
--- /dev/null
+++ b/llvm/test/CodeGen/X86/2010-06-15-FastAllocEarlyCLobber.ll
@@ -0,0 +1,29 @@
+; RUN: llc -regalloc=fast < %s | FileCheck %s
+; PR7382
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
+target triple = "x86_64-unknown-linux-gnu"
+
+@.str = private constant [23 x i8] c"This should be -1: %d\0A\00" ; <[23 x i8]*> [#uses=1]
+
+define i32 @main() {
+entry:
+  %retval = alloca i32, align 4                   ; <i32*> [#uses=3]
+  %v = alloca i32, align 4                        ; <i32*> [#uses=3]
+  store i32 0, i32* %retval
+  %zero = load i32* %retval
+; The earlyclobber register EC0 should not be spilled before the inline asm.
+; Yes, check-not can refer to FileCheck variables defined in the future.
+; CHECK-NOT: [[EC0]]{{.*}}(%rsp)
+; CHECK: bsr {{[^,]*}}, [[EC0:%...]]
+  %0 = call i32 asm "bsr   $1, $0\0A\09cmovz $2, $0", "=&r,ro,r,~{cc},~{dirflag},~{fpsr},~{flags}"(i32 %zero, i32 -1) nounwind, !srcloc !0 ; <i32> [#uses=1]
+  store i32 %0, i32* %v
+  %tmp = load i32* %v                             ; <i32> [#uses=1]
+  %call1 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([23 x i8]* @.str, i32 0, i32 0), i32 %tmp) ; <i32> [#uses=0]
+  store i32 0, i32* %retval
+  %1 = load i32* %retval                          ; <i32> [#uses=1]
+  ret i32 %0
+}
+
+declare i32 @printf(i8*, ...)
+
+!0 = metadata !{i32 191}