swifterror: Don't compute swifterror vregs during instruction selection

The code used llvm basic block predecessors to decided where to insert phi
nodes. Instruction selection can and will liberally insert new machine basic
block predecessors. There is not a guaranteed one-to-one mapping from pred.
llvm basic blocks and machine basic blocks.

Therefore the current approach does not work as it assumes we can mark
predecessor machine basic block as needing a copy, and needs to know the set of
all predecessor machine basic blocks to decide when to insert phis.

Instead of computing the swifterror vregs as we select instructions, propagate
them at the end of instruction selection when the MBB CFG is complete.

When an instruction needs a swifterror vreg and we don't know the value yet,
generate a new vreg and remember this "upward exposed" use, and reconcile this
at the end of instruction selection.

This will only happen if the target supports promoting swifterror parameters to
registers and the swifterror attribute is used.

rdar://28300923

llvm-svn: 283617

1 files changed, 22 insertions, 12 deletions

diff --git a/llvm/test/CodeGen/AArch64/swifterror.ll b/llvm/test/CodeGen/AArch64/swifterror.ll
index 507ae4d37d5..db86afcf6b4 100644
--- a/llvm/test/CodeGen/AArch64/swifterror.ll
+++ b/llvm/test/CodeGen/AArch64/swifterror.ll
@@ -19,10 +19,11 @@ define float @foo(%swift_error** swifterror %error_ptr_ref) {
 ; CHECK-O0-LABEL: foo:
 ; CHECK-O0: orr w{{.*}}, wzr, #0x10
 ; CHECK-O0: malloc
-; CHECK-O0: mov [[ID2:x[0-9]+]], x0
+; CHECK-O0: mov x19, x0
+; CHECK-O0-NOT: x19
 ; CHECK-O0: orr [[ID:w[0-9]+]], wzr, #0x1
+; CHECK-O0-NOT: x19
 ; CHECK-O0: strb [[ID]], [x0, #8]
-; CHECK-O0: mov x19, [[ID2]]
 ; CHECK-O0-NOT: x19
 entry:
   %call = call i8* @malloc(i64 16)
@@ -50,7 +51,7 @@ define float @caller(i8* %error_ref) {
 ; CHECK-O0: mov x19
 ; CHECK-O0: bl {{.*}}foo
 ; CHECK-O0: mov [[ID:x[0-9]+]], x19
-; CHECK-O0: cbnz [[ID]]
+; CHECK-O0: cbnz x19
 entry:
   %error_ptr_ref = alloca swifterror %swift_error*
   store %swift_error* null, %swift_error** %error_ptr_ref
@@ -89,7 +90,7 @@ define float @caller2(i8* %error_ref) {
 ; CHECK-O0: mov x19
 ; CHECK-O0: bl {{.*}}foo
 ; CHECK-O0: mov [[ID:x[0-9]+]], x19
-; CHECK-O0: cbnz [[ID]]
+; CHECK-O0: cbnz x19
 entry:
   %error_ptr_ref = alloca swifterror %swift_error*
   br label %bb_loop
@@ -128,7 +129,7 @@ define float @foo_if(%swift_error** swifterror %error_ptr_ref, i32 %cc) {
 
 ; CHECK-O0-LABEL: foo_if:
 ; spill x19
-; CHECK-O0: str x19
+; CHECK-O0: str x19, [sp, [[SLOT:#[0-9]+]]]
 ; CHECK-O0: cbz w0
 ; CHECK-O0: orr w{{.*}}, wzr, #0x10
 ; CHECK-O0: malloc
@@ -138,7 +139,8 @@ define float @foo_if(%swift_error** swifterror %error_ptr_ref, i32 %cc) {
 ; CHECK-O0: mov x19, [[ID]]
 ; CHECK-O0: ret
 ; reload from stack
-; CHECK-O0: ldr x19
+; CHECK-O0: ldr [[ID3:x[0-9]+]], [sp, [[SLOT]]]
+; CHECK-O0: mov x19, [[ID3]]
 ; CHECK-O0: ret
 entry:
   %cond = icmp ne i32 %cc, 0
@@ -172,18 +174,26 @@ define float @foo_loop(%swift_error** swifterror %error_ptr_ref, i32 %cc, float
 
 ; CHECK-O0-LABEL: foo_loop:
 ; spill x19
-; CHECK-O0: str x19
-; CHECk-O0: cbz
+; CHECK-O0: str x19, [sp, [[SLOT:#[0-9]+]]]
+; CHECK-O0: b [[BB1:[A-Za-z0-9_]*]]
+; CHECK-O0: [[BB1]]:
+; CHECK-O0: ldr     x0, [sp, [[SLOT]]]
+; CHECK-O0: str     x0, [sp, [[SLOT2:#[0-9]+]]]
+; CHECK-O0: cbz {{.*}}, [[BB2:[A-Za-z0-9_]*]]
 ; CHECK-O0: orr w{{.*}}, wzr, #0x10
 ; CHECK-O0: malloc
 ; CHECK-O0: mov [[ID:x[0-9]+]], x0
 ; CHECK-O0: strb w{{.*}}, [{{.*}}[[ID]], #8]
 ; spill x0
-; CHECK-O0: str x0
+; CHECK-O0: str x0, [sp, [[SLOT2]]]
+; CHECK-O0:[[BB2]]:
+; CHECK-O0: ldr     x0, [sp, [[SLOT2]]]
 ; CHECK-O0: fcmp
-; CHECK-O0: b.le
+; CHECK-O0: str     x0, [sp]
+; CHECK-O0: b.le [[BB1]]
 ; reload from stack
-; CHECK-O0: ldr x19
+; CHECK-O0: ldr [[ID3:x[0-9]+]], [sp]
+; CHECK-O0: mov x19, [[ID3]]
 ; CHECK-O0: ret
 entry:
   br label %bb_loop
@@ -272,7 +282,7 @@ define float @caller3(i8* %error_ref) {
 ; CHECK-O0: ldrb [[CODE:w[0-9]+]]
 ; CHECK-O0: ldr [[ID:x[0-9]+]]
 ; CHECK-O0: strb [[CODE]], [{{.*}}[[ID]]]
-; CHECK_O0: bl {{.*}}free
+; CHECK-O0: bl {{.*}}free
 entry:
   %s = alloca %struct.S, align 8
   %error_ptr_ref = alloca swifterror %swift_error*