Remove unused member variable introduced in r165665.

[oota-llvm.git] / lib / Target / ARM / README-Thumb.txt

diff --git a/lib/Target/ARM/README-Thumb.txt b/lib/Target/ARM/README-Thumb.txt
index eed3c54372a6153f931de4317457cc71854e2e5c..463c440852f56c573fe2983cda2634bd862748bb 100644 (file)
--- a/lib/Target/ARM/README-Thumb.txt
+++ b/lib/Target/ARM/README-Thumb.txt
@@ -37,7 +37,7 @@ LPCRELL0:
        mov r1, #PCRELV0
        add r1, pc
        ldr r0, [r0, r1]
-       cpy pc, r0 
+       mov pc, r0 
        .align  2
 LJTI1_0_0:
        .long    LBB1_3
@@ -51,7 +51,7 @@ We should be able to generate:
 LPCRELL0:
        add r1, LJTI1_0_0
        ldr r0, [r0, r1]
-       cpy pc, r0 
+       mov pc, r0 
        .align  2
 LJTI1_0_0:
        .long    LBB1_3
@@ -68,7 +68,7 @@ LPCRELL0:
 
 //===---------------------------------------------------------------------===//
 
-We compiles the following:
+We compile the following:
 
 define i16 @func_entry_2E_ce(i32 %i) {
         switch i32 %i, label %bb12.exitStub [
@@ -196,14 +196,6 @@ This is especially bad when dynamic alloca is used. The all fixed size stack
 objects are referenced off the frame pointer with negative offsets. See
 oggenc for an example.
 
-//===---------------------------------------------------------------------===//
-
-We are reserving R3 as a scratch register under thumb mode. So if it is live in
-to the function, we save / restore R3 to / from R12. Until register scavenging
-is done, we should save R3 to a high callee saved reg at emitPrologue time
-(when hasFP is true or stack size is large) and restore R3 from that register
-instead. This allows us to at least get rid of the save to r12 everytime it is
-used.
 
 //===---------------------------------------------------------------------===//
 
@@ -214,8 +206,8 @@ LPC0:
        add r5, pc
        ldr r6, LCPI1_1
        ldr r2, LCPI1_2
-       cpy r3, r6
-       cpy lr, pc
+       mov r3, r6
+       mov lr, pc
        bx r5
 
 //===---------------------------------------------------------------------===//
@@ -238,3 +230,38 @@ to avoid extra work when we convert Thumb2 instructions to Thumb1 instructions.
 We need to make (some of the) Thumb1 instructions predicable. That will allow
 shrinking of predicated Thumb2 instructions. To allow this, we need to be able
 to toggle the 's' bit since they do not set CPSR when they are inside IT blocks.
+
+//===---------------------------------------------------------------------===//
+
+Make use of hi register variants of cmp: tCMPhir / tCMPZhir.
+
+//===---------------------------------------------------------------------===//
+
+Thumb1 immediate field sometimes keep pre-scaled values. See
+Thumb1RegisterInfo::eliminateFrameIndex. This is inconsistent from ARM and
+Thumb2.
+
+//===---------------------------------------------------------------------===//
+
+Rather than having tBR_JTr print a ".align 2" and constant island pass pad it,
+add a target specific ALIGN instruction instead. That way, GetInstSizeInBytes
+won't have to over-estimate. It can also be used for loop alignment pass.
+
+//===---------------------------------------------------------------------===//
+
+We generate conditional code for icmp when we don't need to. This code:
+
+  int foo(int s) {
+    return s == 1;
+  }
+
+produces:
+
+foo:
+        cmp     r0, #1
+        mov.w   r0, #0
+        it      eq
+        moveq   r0, #1
+        bx      lr
+
+when it could use subs + adcs. This is GCC PR46975.