[X86] Handle COPYs of physregs better (regalloc hints)
Enable enableMultipleCopyHints() on X86.
Original Patch by @jonpa:
While enabling the mischeduler for SystemZ, it was discovered that for some reason a test needed one extra seemingly needless COPY (test/CodeGen/SystemZ/call-03.ll). The handling for that is resulted in this patch, which improves the register coalescing by providing not just one copy hint, but a sorted list of copy hints. On SystemZ, this gives ~12500 less register moves on SPEC, as well as marginally less spilling.
Instead of improving just the SystemZ backend, the improvement has been implemented in common-code (calculateSpillWeightAndHint(). This gives a lot of test failures, but since this should be a general improvement I hope that the involved targets will help and review the test updates.
Differential Revision: https://reviews.llvm.org/D38128
llvm-svn: 342578
diff --git a/llvm/test/CodeGen/X86/sat-add.ll b/llvm/test/CodeGen/X86/sat-add.ll
index 8265a55..5b667d8 100644
--- a/llvm/test/CodeGen/X86/sat-add.ll
+++ b/llvm/test/CodeGen/X86/sat-add.ll
@@ -10,13 +10,14 @@
define i8 @unsigned_sat_constant_i8_using_min(i8 %x) {
; ANY-LABEL: unsigned_sat_constant_i8_using_min:
; ANY: # %bb.0:
-; ANY-NEXT: cmpb $-43, %dil
+; ANY-NEXT: movl %edi, %eax
+; ANY-NEXT: cmpb $-43, %al
; ANY-NEXT: jb .LBB0_2
; ANY-NEXT: # %bb.1:
-; ANY-NEXT: movb $-43, %dil
+; ANY-NEXT: movb $-43, %al
; ANY-NEXT: .LBB0_2:
-; ANY-NEXT: addb $42, %dil
-; ANY-NEXT: movl %edi, %eax
+; ANY-NEXT: addb $42, %al
+; ANY-NEXT: # kill: def $al killed $al killed $eax
; ANY-NEXT: retq
%c = icmp ult i8 %x, -43
%s = select i1 %c, i8 %x, i8 -43
@@ -190,15 +191,16 @@
define i8 @unsigned_sat_variable_i8_using_min(i8 %x, i8 %y) {
; ANY-LABEL: unsigned_sat_variable_i8_using_min:
; ANY: # %bb.0:
-; ANY-NEXT: movl %esi, %eax
-; ANY-NEXT: notb %al
-; ANY-NEXT: cmpb %al, %dil
+; ANY-NEXT: movl %edi, %eax
+; ANY-NEXT: movl %esi, %ecx
+; ANY-NEXT: notb %cl
+; ANY-NEXT: cmpb %cl, %al
; ANY-NEXT: jb .LBB12_2
; ANY-NEXT: # %bb.1:
-; ANY-NEXT: movl %eax, %edi
+; ANY-NEXT: movl %ecx, %eax
; ANY-NEXT: .LBB12_2:
-; ANY-NEXT: addb %sil, %dil
-; ANY-NEXT: movl %edi, %eax
+; ANY-NEXT: addb %sil, %al
+; ANY-NEXT: # kill: def $al killed $al killed $eax
; ANY-NEXT: retq
%noty = xor i8 %y, -1
%c = icmp ult i8 %x, %noty