[llvm-branch-commits] [llvm-branch] r196769 - Merge r196725 (conflicts on same API as before):

[Tim Northover]

Author: tnorthover
Date: Mon Dec  9 03:05:30 2013
New Revision: 196769

URL: http://llvm.org/viewvc/llvm-project?rev=196769&view=rev
Log:
Merge r196725 (conflicts on same API as before):
------------------------------------------------------------------------
r196725 | tnorthover | 2013-12-08 15:56:50 +0000 (Sun, 08 Dec 2013) |
19 lines

ARM: fix folding of stack-adjustment (yet again).

When trying to eliminate an "sub sp, sp, #N" instruction by folding
it into an existing push/pop using dummy registers, we need to account
for the fact that this might affect precisely how "fp" gets set in the
prologue.

We were attempting this, but assuming that *whenever* we performed a
fold it would make a difference. This is false, for example, in:
    push {r4, r7, lr}
    add fp, sp, #4
    vpush {d8}
    sub sp, sp, #8

we can fold the "sub" into the "vpush", forming "vpush {d7, d8}".
However, in that case the "add fp" instruction mustn't change, which
we were getting wrong before.

Should fix PR18160.
------------------------------------------------------------------------

Modified:
    llvm/branches/release_34/   (props changed)
    llvm/branches/release_34/lib/Target/ARM/ARMFrameLowering.cpp
    llvm/branches/release_34/test/CodeGen/ARM/fold-stack-adjust.ll

Propchange: llvm/branches/release_34/
------------------------------------------------------------------------------
--- svn:mergeinfo (original)
+++ svn:mergeinfo Mon Dec  9 03:05:30 2013
@@ -1,3 +1,3 @@
 /llvm/branches/Apple/Pertwee:110850,110961
 /llvm/branches/type-system-rewrite:133420-134817
-/llvm/trunk:155241,195092-195094,195100,195102-195103,195118,195129,195136,195138,195148,195152,195156-195157,195161-195162,195193,195272,195317-195318,195327,195330,195333,195339,195343,195355,195364,195379,195397-195399,195401,195408,195421,195423-195424,195432,195439,195444,195455-195456,195469,195476-195477,195479,195491-195495,195514,195528,195547,195567,195573-195576,195590-195591,195599,195632,195635-195636,195670,195677,195679,195682,195684,195713,195716,195769,195773,195779,195782,195787-195788,195791,195803,195812,195827,195834,195843-195844,195878-195881,195887,195903,195905,195912,195915,195932,195936-195943,195972-195973,195975-195976,196004,196044-196046,196069,196100,196104,196129,196151,196153,196189-196192,196198-196199,196208-196209,196211,196261,196267,196269,196294,196359-196362,196369,196391,196456,196493,196508,196532-196533,196535,196538,196588,196611,196637-196638,196658,196668,196735,196751,196755
+/llvm/trunk:155241,195092-195094,195100,195102-195103,195118,195129,195136,195138,195148,195152,195156-195157,195161-195162,195193,195272,195317-195318,195327,195330,195333,195339,195343,195355,195364,195379,195397-195399,195401,195408,195421,195423-195424,195432,195439,195444,195455-195456,195469,195476-195477,195479,195491-195495,195514,195528,195547,195567,195573-195576,195590-195591,195599,195632,195635-195636,195670,195677,195679,195682,195684,195713,195716,195769,195773,195779,195782,195787-195788,195791,195803,195812,195827,195834,195843-195844,195878-195881,195887,195903,195905,195912,195915,195932,195936-195943,195972-195973,195975-195976,196004,196044-196046,196069,196100,196104,196129,196151,196153,196189-196192,196198-196199,196208-196209,196211,196261,196267,196269,196294,196359-196362,196369,196391,196456,196493,196508,196532-196533,196535,196538,196588,196611,196637-196638,196658,196668,196725,196735,196751,196755

Modified: llvm/branches/release_34/lib/Target/ARM/ARMFrameLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_34/lib/Target/ARM/ARMFrameLowering.cpp?rev=196769&r1=196768&r2=196769&view=diff
==============================================================================
--- llvm/branches/release_34/lib/Target/ARM/ARMFrameLowering.cpp (original)
+++ llvm/branches/release_34/lib/Target/ARM/ARMFrameLowering.cpp Mon Dec  9 03:05:30 2013
@@ -256,9 +256,10 @@ void ARMFrameLowering::emitPrologue(Mach
 
   if (NumBytes) {
     // Adjust SP after all the callee-save spills.
-    if (tryFoldSPUpdateIntoPushPop(MF, LastPush, NumBytes))
-      FramePtrOffsetInPush += NumBytes;
-    else
+    if (tryFoldSPUpdateIntoPushPop(MF, LastPush, NumBytes)) {
+      if (LastPush == FramePtrPush)
+        FramePtrOffsetInPush += NumBytes;
+    } else
       emitSPUpdate(isARM, MBB, MBBI, dl, TII, -NumBytes,
                    MachineInstr::FrameSetup);
 

Modified: llvm/branches/release_34/test/CodeGen/ARM/fold-stack-adjust.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_34/test/CodeGen/ARM/fold-stack-adjust.ll?rev=196769&r1=196768&r2=196769&view=diff
==============================================================================
--- llvm/branches/release_34/test/CodeGen/ARM/fold-stack-adjust.ll (original)
+++ llvm/branches/release_34/test/CodeGen/ARM/fold-stack-adjust.ll Mon Dec  9 03:05:30 2013
@@ -137,6 +137,15 @@ define void @test_fold_point(i1 %tst) mi
 ; CHECK: {{LBB[0-9]+_2}}:
 ; CHECK-NEXT: vpop {d7, d8}
 ; CHECK-NEXT: pop {r4, pc}
+
+  ; With a guaranteed frame-pointer, we want to make sure that its offset in the
+  ; push block is correct, even if a few registers have been tacked onto a later
+  ; vpush (PR18160).
+; CHECK-IOS-LABEL: test_fold_point:
+; CHECK-IOS: push {r4, r7, lr}
+; CHECK-IOS-NEXT: add r7, sp, #4
+; CHECK-IOS-NEXT: vpush {d7, d8}
+
   ; We want some memory so there's a stack adjustment to fold...
   %var = alloca i8, i32 8