Coalescer should not delete extract_subreg, insert_subreg, and subreg_to_reg of

physical registers. This is especially critical for the later two since they
start the live interval of a super-register. e.g.
%DO<def> = INSERT_SUBREG %D0<undef>, %S0<kill>, 1
If this instruction is eliminated, the register scavenger will not be happy as
D0 is not defined previously.
This fixes PR5055.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82968 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 24 insertions, 0 deletions

diff --git a/test/CodeGen/ARM/2009-09-27-CoalescerBug.ll b/test/CodeGen/ARM/2009-09-27-CoalescerBug.ll
new file mode 100644
index 0000000000..ea2693ac2e
--- /dev/null
+++ b/test/CodeGen/ARM/2009-09-27-CoalescerBug.ll
@@ -0,0 +1,24 @@
+; RUN: llc < %s -mtriple=armv7-eabi -mcpu=cortex-a8
+; PR5055
+
+module asm ".globl\09__aeabi_f2lz"
+module asm ".set\09__aeabi_f2lz, __fixsfdi"
+module asm ""
+
+define arm_aapcs_vfpcc i64 @__fixsfdi(float %a) nounwind {
+entry:
+  %0 = fcmp olt float %a, 0.000000e+00            ; <i1> [#uses=1]
+  br i1 %0, label %bb, label %bb1
+
+bb:                                               ; preds = %entry
+  %1 = fsub float -0.000000e+00, %a               ; <float> [#uses=1]
+  %2 = tail call arm_aapcs_vfpcc  i64 @__fixunssfdi(float %1) nounwind ; <i64> [#uses=1]
+  %3 = sub i64 0, %2                              ; <i64> [#uses=1]
+  ret i64 %3
+
+bb1:                                              ; preds = %entry
+  %4 = tail call arm_aapcs_vfpcc  i64 @__fixunssfdi(float %a) nounwind ; <i64> [#uses=1]
+  ret i64 %4
+}
+
+declare arm_aapcs_vfpcc i64 @__fixunssfdi(float)